TWAIN suddenly requires admin privileges

This one mystifies me. I tried to scan a document the other day and the
Epson scanner software wouldn't start. That wasn't true a couple or
three weeks ago...

I'll try to keep it short[1]. I have two scanners (printers, really).
The Brother printer's software would start but after clicking on Scan,
I was told that the printer couldn't be found.

I tried IrfanView. The Select Scan/TWAIN Source dialog was empty - it
had nothing to select from either printer.

For some reason, I had the idea to try right clicking all three
programs and running as Administrator (even though this is an Admin
account) and all three worked fine, once I said yes to UAC.

The other computer here is also W7, and its scanner SW (that computer
is only set up for the Epson) starts up without being in Admin mode.

I checked permissions (from the real Administrator account) in the
windows\twain_32 directory; they all look OK. I did a system restore to
the time before I had installed Avast free and AVG free (both had been
uninstalled), and it made no difference. I also took out the external
video card and the extra USB3 card, and nothing changed.

This is an Asus P8H67-M EVO MB, Core i5 2500 MHz, 8 GB of DDR3
PC3-10600 memory, running W7 Pro, put together in March 2012.

There is the obvious work-around, namely run the programs as
Administrator, but I would like to have other ideas to try. For one
thing, other things might be sick that I haven't discovered yet :-(

[1] Honestly, I did try :-)

--
Gene E. Bloch (Stumbling Bloch)

On 3/07/2014, Gene E. Bloch posted:
....

I also took out the
external video card and the extra USB3 card, and nothing changed.

Sorry, that's an error. I did that for another reason, namely memory
testing.

And I forgot to mention that the connection to both printers (All in
Ones) is wireless only.

....

--
Gene E. Bloch (Stumbling Bloch)

Gene E. Bloch wrote:
This one mystifies me. I tried to scan a document the other day and the
Epson scanner software wouldn't start. That wasn't true a couple or
three weeks ago...

I'll try to keep it short[1]. I have two scanners (printers, really).
The Brother printer's software would start but after clicking on Scan, I
was told that the printer couldn't be found.

I tried IrfanView. The Select Scan/TWAIN Source dialog was empty - it
had nothing to select from either printer.

For some reason, I had the idea to try right clicking all three programs
and running as Administrator (even though this is an Admin account) and
all three worked fine, once I said yes to UAC.

The other computer here is also W7, and its scanner SW (that computer is
only set up for the Epson) starts up without being in Admin mode.

I checked permissions (from the real Administrator account) in the
windows\twain_32 directory; they all look OK. I did a system restore to
the time before I had installed Avast free and AVG free (both had been
uninstalled), and it made no difference. I also took out the external
video card and the extra USB3 card, and nothing changed.

This is an Asus P8H67-M EVO MB, Core i5 2500 MHz, 8 GB of DDR3 PC3-10600
memory, running W7 Pro, put together in March 2012.

There is the obvious work-around, namely run the programs as
Administrator, but I would like to have other ideas to try. For one
thing, other things might be sick that I haven't discovered yet :-(

[1] Honestly, I did try :-)


The first hit I get in a search, has a regedit suggestion.

*******

I have an app that is using a scanner via TWAIN. If I am logged in as
Admin, the device shows up in the list, but if not it doesn't.

This is with Win XP.

Any thoughts on what to do for the user to allow the access without making
them a complete admin?

--------

For [anyone who wants] to know the answer:

Do the following and try the one at a time, starting with step 1:

* in regedit, grant full control to that user for the key
HKLM\SOFTWARE\Scanner Information

if that doesn't work:
* grant full control to that user or Users group for
HKLM\SYSTEM\CurrentControl\Control\StillImage

*******

That seems to align with some dialog box not listing the device.
An attempt is being made to read the registry key, and that
is failing. You can prove that for yourself, by running
Process Monitor, then stop the capture later and review
what happens when the software consults (or attempts to consult)
those keys.

Paul

On 3/07/2014, Paul posted:
Gene E. Bloch wrote:
This one mystifies me. I tried to scan a document the other day and
the Epson scanner software wouldn't start. That wasn't true a
couple or three weeks ago...

I'll try to keep it short[1]. I have two scanners (printers,
really). The Brother printer's software would start but after
clicking on Scan, I was told that the printer couldn't be found.

I tried IrfanView. The Select Scan/TWAIN Source dialog was empty -
it had nothing to select from either printer.

For some reason, I had the idea to try right clicking all three
programs and running as Administrator (even though this is an Admin
account) and all three worked fine, once I said yes to UAC.

The other computer here is also W7, and its scanner SW (that
computer is only set up for the Epson) starts up without being in
Admin mode.

I checked permissions (from the real Administrator account) in the
windows\twain_32 directory; they all look OK. I did a system
restore to the time before I had installed Avast free and AVG free
(both had been uninstalled), and it made no difference. I also took
out the external video card and the extra USB3 card, and nothing
changed.

This is an Asus P8H67-M EVO MB, Core i5 2500 MHz, 8 GB of DDR3
PC3-10600 memory, running W7 Pro, put together in March 2012.

There is the obvious work-around, namely run the programs as
Administrator, but I would like to have other ideas to try. For one
thing, other things might be sick that I haven't discovered yet :-(

[1] Honestly, I did try :-)


The first hit I get in a search, has a regedit suggestion.

Thanks. I will investigate later, but it's too late today...

I tried at least five Google searches with variants on my search
string, and I turned up nothing useful. How did you manage to find what
you posted? :-)

My strings were items like "TWAIN requires Administrator", "Scanner
TWAIN not found", "Permissions for TWAIN drivers", and more. Come to
think of it, I tried a good bit more than five strings. I got a couple
of hits over and over again, and many hits on Mark Twain. Using Scanner
instead of TWAIN made it worse...

What string did you search for?

I used to be really lousy at Google searches, but eventually I got a
lot better. However, I realized that the difference was Google's
algorithms, not my skill at concocting search strings :-)
....

--
Gene E. Bloch (Stumbling Bloch)

When my devices on my LAN vanished it turns out that the router changed
their IP address. probably because i added or removed something on the
LAN. I had to track it down and re-enter the IP on the PC. I went to
the multifunction printer / scanner / fax / copier I set a fixed IP
address. Now no more problems.
Other devices have there own applications that can locate them and
automatically adjust their IP addresses.



--- news://freenews.netfront.net/ - complaints: ---

Gene E. Bloch wrote:
On 3/07/2014, Paul posted:
Gene E. Bloch wrote:
This one mystifies me. I tried to scan a document the other day and
the Epson scanner software wouldn't start. That wasn't true a couple
or three weeks ago...

I'll try to keep it short[1]. I have two scanners (printers, really).
The Brother printer's software would start but after clicking on
Scan, I was told that the printer couldn't be found.

I tried IrfanView. The Select Scan/TWAIN Source dialog was empty - it
had nothing to select from either printer.

For some reason, I had the idea to try right clicking all three
programs and running as Administrator (even though this is an Admin
account) and all three worked fine, once I said yes to UAC.

The other computer here is also W7, and its scanner SW (that computer
is only set up for the Epson) starts up without being in Admin mode.

I checked permissions (from the real Administrator account) in the
windows\twain_32 directory; they all look OK. I did a system restore
to the time before I had installed Avast free and AVG free (both had
been uninstalled), and it made no difference. I also took out the
external video card and the extra USB3 card, and nothing changed.

This is an Asus P8H67-M EVO MB, Core i5 2500 MHz, 8 GB of DDR3
PC3-10600 memory, running W7 Pro, put together in March 2012.

There is the obvious work-around, namely run the programs as
Administrator, but I would like to have other ideas to try. For one
thing, other things might be sick that I haven't discovered yet :-(

[1] Honestly, I did try :-)


The first hit I get in a search, has a regedit suggestion.

Thanks. I will investigate later, but it's too late today...

I tried at least five Google searches with variants on my search string,
and I turned up nothing useful. How did you manage to find what you
posted? :-)

My strings were items like "TWAIN requires Administrator", "Scanner
TWAIN not found", "Permissions for TWAIN drivers", and more. Come to
think of it, I tried a good bit more than five strings. I got a couple
of hits over and over again, and many hits on Mark Twain. Using Scanner
instead of TWAIN made it worse...

What string did you search for?

I used to be really lousy at Google searches, but eventually I got a lot
better. However, I realized that the difference was Google's algorithms,
not my skill at concocting search strings :-)
...


Checking the history on my browser, it was

"twain windows 7 administrator"

The funny thing is, the link I found now isn't showing up
in the search.

Paul

On 3/08/2014, Paul posted:
Gene E. Bloch wrote:
On 3/07/2014, Paul posted:
Gene E. Bloch wrote:
This one mystifies me. I tried to scan a document the other day
and the Epson scanner software wouldn't start. That wasn't true a
couple or three weeks ago...

I'll try to keep it short[1]. I have two scanners (printers,
really). The Brother printer's software would start but after
clicking on Scan, I was told that the printer couldn't be found.

I tried IrfanView. The Select Scan/TWAIN Source dialog was empty
- it had nothing to select from either printer.

For some reason, I had the idea to try right clicking all three
programs and running as Administrator (even though this is an
Admin account) and all three worked fine, once I said yes to UAC.

The other computer here is also W7, and its scanner SW (that
computer is only set up for the Epson) starts up without being in
Admin mode.

I checked permissions (from the real Administrator account) in
the windows\twain_32 directory; they all look OK. I did a system
restore to the time before I had installed Avast free and AVG
free (both had been uninstalled), and it made no difference. I
also took out the external video card and the extra USB3 card,
and nothing changed.

This is an Asus P8H67-M EVO MB, Core i5 2500 MHz, 8 GB of DDR3
PC3-10600 memory, running W7 Pro, put together in March 2012.

There is the obvious work-around, namely run the programs as
Administrator, but I would like to have other ideas to try. For
one thing, other things might be sick that I haven't discovered
yet :-(

[1] Honestly, I did try :-)


The first hit I get in a search, has a regedit suggestion.

Thanks. I will investigate later, but it's too late today...

I tried at least five Google searches with variants on my search
string, and I turned up nothing useful. How did you manage to find
what you posted? :-)

My strings were items like "TWAIN requires Administrator", "Scanner
TWAIN not found", "Permissions for TWAIN drivers", and more. Come
to think of it, I tried a good bit more than five strings. I got a
couple of hits over and over again, and many hits on Mark Twain.
Using Scanner instead of TWAIN made it worse...

What string did you search for?

I used to be really lousy at Google searches, but eventually I got
a lot better. However, I realized that the difference was Google's
algorithms, not my skill at concocting search strings :-)
...

Checking the history on my browser, it was

"twain windows 7 administrator"

The funny thing is, the link I found now isn't showing up
in the search.

Paul

Thanks, Paul.

I'll see if I have better luck with it than you are having right now.

OK...I took a quick look and I don't see anything that seems to address
my personal bugbear here.

BTW, what really bothers me about this, which I forgot to emphasize in
my OP, is that two or three weeks ago the problem wasn't present. Where
the hell did it come from?

Anyway, first things first: I'll try your reg hacks in a few minutes.

--
Gene E. Bloch (Stumbling Bloch)

On 3/07/2014, OldGuy posted:
When my devices on my LAN vanished it turns out that the router
changed their IP address. probably because i added or removed
something on the LAN. I had to track it down and re-enter the IP on
the PC. I went to the multifunction printer / scanner / fax / copier
I set a fixed IP address. Now no more problems.
Other devices have there own applications that can locate them and
automatically adjust their IP addresses.

The printers continue to print. Their IP addresses aren't changed, and
their web pages remain available. It's only the scanner part that is a
problem. And only on one computer out of two.

Thanks - I should have mentioned in my OP that access is still partly
OK :-)

--
Gene E. Bloch (Stumbling Bloch)

On 3/07/2014, Paul posted:
Gene E. Bloch wrote:
This one mystifies me. I tried to scan a document the other day and
the Epson scanner software wouldn't start. That wasn't true a
couple or three weeks ago...

I'll try to keep it short[1]. I have two scanners (printers,
really). The Brother printer's software would start but after
clicking on Scan, I was told that the printer couldn't be found.

I tried IrfanView. The Select Scan/TWAIN Source dialog was empty -
it had nothing to select from either printer.

For some reason, I had the idea to try right clicking all three
programs and running as Administrator (even though this is an Admin
account) and all three worked fine, once I said yes to UAC.

The other computer here is also W7, and its scanner SW (that
computer is only set up for the Epson) starts up without being in
Admin mode.

I checked permissions (from the real Administrator account) in the
windows\twain_32 directory; they all look OK. I did a system
restore to the time before I had installed Avast free and AVG free
(both had been uninstalled), and it made no difference. I also took
out the external video card and the extra USB3 card, and nothing
changed.

This is an Asus P8H67-M EVO MB, Core i5 2500 MHz, 8 GB of DDR3
PC3-10600 memory, running W7 Pro, put together in March 2012.

There is the obvious work-around, namely run the programs as
Administrator, but I would like to have other ideas to try. For one
thing, other things might be sick that I haven't discovered yet :-(

[1] Honestly, I did try :-)


The first hit I get in a search, has a regedit suggestion.

*******

I have an app that is using a scanner via TWAIN. If I am logged
in as
Admin, the device shows up in the list, but if not it doesn't.

This is with Win XP.

Any thoughts on what to do for the user to allow the access
without making
them a complete admin?

--------

For [anyone who wants] to know the answer:

Do the following and try the one at a time, starting with step 1:

* in regedit, grant full control to that user for the key
HKLM\SOFTWARE\Scanner Information

if that doesn't work:
* grant full control to that user or Users group for
HKLM\SYSTEM\CurrentControl\Control\StillImage

*******

That seems to align with some dialog box not listing the device.
An attempt is being made to read the registry key, and that
is failing. You can prove that for yourself, by running
Process Monitor, then stop the capture later and review
what happens when the software consults (or attempts to consult)
those keys.

Paul

The first key doesn't exist in my registry.

The second key gives full control to Administrators (this is an admin
account) but not to users. If I change permissions for Users, or add my
own account to the permissions list, Full control is not offered in the
dialog.

I'll log on as root and see what I can see.

--
Gene E. Bloch (Stumbling Bloch)

On 3/08/2014, Gene E. Bloch posted:
On 3/07/2014, Paul posted:
Gene E. Bloch wrote:
This one mystifies me. I tried to scan a document the other day
and the Epson scanner software wouldn't start. That wasn't true a
couple or three weeks ago...

I'll try to keep it short[1]. I have two scanners (printers,
really). The Brother printer's software would start but after
clicking on Scan, I was told that the printer couldn't be found.

I tried IrfanView. The Select Scan/TWAIN Source dialog was empty -
it had nothing to select from either printer.

For some reason, I had the idea to try right clicking all three
programs and running as Administrator (even though this is an
Admin account) and all three worked fine, once I said yes to UAC.

The other computer here is also W7, and its scanner SW (that
computer is only set up for the Epson) starts up without being in
Admin mode.

I checked permissions (from the real Administrator account) in the
windows\twain_32 directory; they all look OK. I did a system
restore to the time before I had installed Avast free and AVG free
(both had been uninstalled), and it made no difference. I also
took out the external video card and the extra USB3 card, and
nothing changed.

This is an Asus P8H67-M EVO MB, Core i5 2500 MHz, 8 GB of DDR3
PC3-10600 memory, running W7 Pro, put together in March 2012.

There is the obvious work-around, namely run the programs as
Administrator, but I would like to have other ideas to try. For
one thing, other things might be sick that I haven't discovered
yet :-(

[1] Honestly, I did try :-)


The first hit I get in a search, has a regedit suggestion.

*******

I have an app that is using a scanner via TWAIN. If I am
logged in as
Admin, the device shows up in the list, but if not it doesn't.

This is with Win XP.

Any thoughts on what to do for the user to allow the access
without making
them a complete admin?

--------

For [anyone who wants] to know the answer:

Do the following and try the one at a time, starting with step
1:

* in regedit, grant full control to that user for the key
HKLM\SOFTWARE\Scanner Information

if that doesn't work:
* grant full control to that user or Users group for
HKLM\SYSTEM\CurrentControl\Control\StillImage

*******

That seems to align with some dialog box not listing the device.
An attempt is being made to read the registry key, and that
is failing. You can prove that for yourself, by running
Process Monitor, then stop the capture later and review
what happens when the software consults (or attempts to consult)
those keys.

Paul

The first key doesn't exist in my registry.

The second key gives full control to Administrators (this is an admin
account) but not to users. If I change permissions for Users, or add
my own account to the permissions list, Full control is not offered
in the dialog.

I'll log on as root and see what I can see.

As root, I was able to give Users full control; Administrator users
already had it.

I rebooted and made sure the key got the new permission before checking
the TWAIN behavior. There was no change in the TWAIN behavior.

--
Gene E. Bloch (Stumbling Bloch)

Gene E. Bloch wrote:
On 3/08/2014, Gene E. Bloch posted:
On 3/07/2014, Paul posted:
Gene E. Bloch wrote:
This one mystifies me. I tried to scan a document the other day and
the Epson scanner software wouldn't start. That wasn't true a couple
or three weeks ago...

I'll try to keep it short[1]. I have two scanners (printers,
really). The Brother printer's software would start but after
clicking on Scan, I was told that the printer couldn't be found.

I tried IrfanView. The Select Scan/TWAIN Source dialog was empty -
it had nothing to select from either printer.

For some reason, I had the idea to try right clicking all three
programs and running as Administrator (even though this is an Admin
account) and all three worked fine, once I said yes to UAC.

The other computer here is also W7, and its scanner SW (that
computer is only set up for the Epson) starts up without being in
Admin mode.

I checked permissions (from the real Administrator account) in the
windows\twain_32 directory; they all look OK. I did a system restore
to the time before I had installed Avast free and AVG free (both had
been uninstalled), and it made no difference. I also took out the
external video card and the extra USB3 card, and nothing changed.

This is an Asus P8H67-M EVO MB, Core i5 2500 MHz, 8 GB of DDR3
PC3-10600 memory, running W7 Pro, put together in March 2012.

There is the obvious work-around, namely run the programs as
Administrator, but I would like to have other ideas to try. For one
thing, other things might be sick that I haven't discovered yet :-(

[1] Honestly, I did try :-)


The first hit I get in a search, has a regedit suggestion.

*******

I have an app that is using a scanner via TWAIN. If I am logged
in as
Admin, the device shows up in the list, but if not it doesn't.

This is with Win XP.

Any thoughts on what to do for the user to allow the access
without making
them a complete admin?

--------

For [anyone who wants] to know the answer:

Do the following and try the one at a time, starting with step 1:

* in regedit, grant full control to that user for the key
HKLM\SOFTWARE\Scanner Information

if that doesn't work:
* grant full control to that user or Users group for
HKLM\SYSTEM\CurrentControl\Control\StillImage

*******

That seems to align with some dialog box not listing the device.
An attempt is being made to read the registry key, and that
is failing. You can prove that for yourself, by running
Process Monitor, then stop the capture later and review
what happens when the software consults (or attempts to consult)
those keys.

Paul

The first key doesn't exist in my registry.

The second key gives full control to Administrators (this is an admin
account) but not to users. If I change permissions for Users, or add
my own account to the permissions list, Full control is not offered in
the dialog.

I'll log on as root and see what I can see.

As root, I was able to give Users full control; Administrator users
already had it.

I rebooted and made sure the key got the new permission before checking
the TWAIN behavior. There was no change in the TWAIN behavior.


I don't have anything here, to reproduce a TWAIN setup with.
Try Process Monitor from Sysinternals.com, do a trace without
any filter entries, and have a look at what is happening.
Maybe you'll get a hint that way.

In the file menu of ProcMon, you untick the capture item, to
stop tracing. And then you can go through the log, looking
for anything relevant. You would go through the motions
of trying to access the TWAIN device, while ProcMon is
capturing, then when it fails, you can go back to ProcMon
and stop the capturing.

Paul

On 3/08/2014, Paul posted:
Gene E. Bloch wrote:
On 3/08/2014, Gene E. Bloch posted:
On 3/07/2014, Paul posted:
Gene E. Bloch wrote:
This one mystifies me. I tried to scan a document the other day
and the Epson scanner software wouldn't start. That wasn't true
a couple or three weeks ago...

I'll try to keep it short[1]. I have two scanners (printers,
really). The Brother printer's software would start but after
clicking on Scan, I was told that the printer couldn't be found.

I tried IrfanView. The Select Scan/TWAIN Source dialog was empty
- it had nothing to select from either printer.

For some reason, I had the idea to try right clicking all three
programs and running as Administrator (even though this is an
Admin account) and all three worked fine, once I said yes to
UAC.

The other computer here is also W7, and its scanner SW (that
computer is only set up for the Epson) starts up without being
in Admin mode.

I checked permissions (from the real Administrator account) in
the windows\twain_32 directory; they all look OK. I did a system
restore to the time before I had installed Avast free and AVG
free (both had been uninstalled), and it made no difference. I
also took out the external video card and the extra USB3 card,
and nothing changed.

This is an Asus P8H67-M EVO MB, Core i5 2500 MHz, 8 GB of DDR3
PC3-10600 memory, running W7 Pro, put together in March 2012.

There is the obvious work-around, namely run the programs as
Administrator, but I would like to have other ideas to try. For
one thing, other things might be sick that I haven't discovered
yet :-(

[1] Honestly, I did try :-)


The first hit I get in a search, has a regedit suggestion.

*******

I have an app that is using a scanner via TWAIN. If I am
logged in as
Admin, the device shows up in the list, but if not it
doesn't.

This is with Win XP.

Any thoughts on what to do for the user to allow the access
without making
them a complete admin?

--------

For [anyone who wants] to know the answer:

Do the following and try the one at a time, starting with
step 1:

* in regedit, grant full control to that user for the key
HKLM\SOFTWARE\Scanner Information

if that doesn't work:
* grant full control to that user or Users group for
HKLM\SYSTEM\CurrentControl\Control\StillImage

*******

That seems to align with some dialog box not listing the device.
An attempt is being made to read the registry key, and that
is failing. You can prove that for yourself, by running
Process Monitor, then stop the capture later and review
what happens when the software consults (or attempts to consult)
those keys.

Paul

The first key doesn't exist in my registry.

The second key gives full control to Administrators (this is an
admin account) but not to users. If I change permissions for
Users, or add my own account to the permissions list, Full control
is not offered in the dialog.

I'll log on as root and see what I can see.

As root, I was able to give Users full control; Administrator users
already had it.

I rebooted and made sure the key got the new permission before
checking the TWAIN behavior. There was no change in the TWAIN
behavior.


I don't have anything here, to reproduce a TWAIN setup with.
Try Process Monitor from Sysinternals.com, do a trace without
any filter entries, and have a look at what is happening.
Maybe you'll get a hint that way.

In the file menu of ProcMon, you untick the capture item, to
stop tracing. And then you can go through the log, looking
for anything relevant. You would go through the motions
of trying to access the TWAIN device, while ProcMon is
capturing, then when it fails, you can go back to ProcMon
and stop the capturing.

Paul

OK. Tomorrow, though.

I put a link on my destop as a reminder.

--
Gene E. Bloch (Stumbling Bloch)

On Fri, 07 Mar 2014 16:04:18 -0800, Gene E. Bloch
wrote:

This one mystifies me. I tried to scan a document the other day and the
Epson scanner software wouldn't start. That wasn't true a couple or
three weeks ago...

This has similarities to an experience that I had in the past couple
of weeks.

My adventure was a migration from Win7x64 through to Win81x64. My PC
has a Canon MP610 printer (with built-in scanner) attached. Although,
as part of the Win8 installation, I checked that the printer would
print, it was a few more days before I tried to scan a document - and,
no twain driver could be found!!

As part of the Win8 install, I allowed the OS to install the printer
driver - my mistake!!

My next move was to download the latest x64 driver for the MP610 from
Canon, then uninstall the OS provided driver. I then installed the
new driver from Canon and the scanner then worked as expected.

Now, this may have nothing to do with your problem. It is, however,
the best I can offer.

On 3/11/2014, Monty posted:
On Fri, 07 Mar 2014 16:04:18 -0800, Gene E. Bloch
wrote:

This one mystifies me. I tried to scan a document the other day and
the Epson scanner software wouldn't start. That wasn't true a
couple or three weeks ago...

This has similarities to an experience that I had in the past couple
of weeks.

My adventure was a migration from Win7x64 through to Win81x64. My PC
has a Canon MP610 printer (with built-in scanner) attached.
Although, as part of the Win8 installation, I checked that the
printer would print, it was a few more days before I tried to scan a
document - and, no twain driver could be found!!

As part of the Win8 install, I allowed the OS to install the printer
driver - my mistake!!

My next move was to download the latest x64 driver for the MP610 from
Canon, then uninstall the OS provided driver. I then installed the
new driver from Canon and the scanner then worked as expected.

Now, this may have nothing to do with your problem. It is, however,
the best I can offer.

Go back to my post and read it. It should be clear from the part you
didn't quote that your situation is unrelated to mine.

A couple of weeks ago, two programs could each scan with their
respective scanner and a third program could scan from both of those
scanners, and none required running as Administrator.

Last week none of the above programs could see the scanner unless I ran
the programs as Administrator.

There were no other changes, AFAICT. Definitely no new OS and
definitely no new drivers (for either MFP).

--
Gene E. Bloch (Stumbling Bloch)

On Sat, 08 Mar 2014 20:49:38 -0500, Paul wrote:

Gene E. Bloch wrote:
On 3/08/2014, Gene E. Bloch posted:
On 3/07/2014, Paul posted:
Gene E. Bloch wrote:
This one mystifies me. I tried to scan a document the other day and
the Epson scanner software wouldn't start. That wasn't true a couple
or three weeks ago...

I'll try to keep it short[1]. I have two scanners (printers,
really). The Brother printer's software would start but after
clicking on Scan, I was told that the printer couldn't be found.

I tried IrfanView. The Select Scan/TWAIN Source dialog was empty -
it had nothing to select from either printer.

For some reason, I had the idea to try right clicking all three
programs and running as Administrator (even though this is an Admin
account) and all three worked fine, once I said yes to UAC.

The other computer here is also W7, and its scanner SW (that
computer is only set up for the Epson) starts up without being in
Admin mode.

I checked permissions (from the real Administrator account) in the
windows\twain_32 directory; they all look OK. I did a system restore
to the time before I had installed Avast free and AVG free (both had
been uninstalled), and it made no difference. I also took out the
external video card and the extra USB3 card, and nothing changed.

This is an Asus P8H67-M EVO MB, Core i5 2500 MHz, 8 GB of DDR3
PC3-10600 memory, running W7 Pro, put together in March 2012.

There is the obvious work-around, namely run the programs as
Administrator, but I would like to have other ideas to try. For one
thing, other things might be sick that I haven't discovered yet :-(

[1] Honestly, I did try :-)


The first hit I get in a search, has a regedit suggestion.

*******

I have an app that is using a scanner via TWAIN. If I am logged
in as
Admin, the device shows up in the list, but if not it doesn't.

This is with Win XP.

Any thoughts on what to do for the user to allow the access
without making
them a complete admin?

--------

For [anyone who wants] to know the answer:

Do the following and try the one at a time, starting with step 1:

* in regedit, grant full control to that user for the key
HKLM\SOFTWARE\Scanner Information

if that doesn't work:
* grant full control to that user or Users group for
HKLM\SYSTEM\CurrentControl\Control\StillImage

*******

That seems to align with some dialog box not listing the device.
An attempt is being made to read the registry key, and that
is failing. You can prove that for yourself, by running
Process Monitor, then stop the capture later and review
what happens when the software consults (or attempts to consult)
those keys.

Paul

The first key doesn't exist in my registry.

The second key gives full control to Administrators (this is an admin
account) but not to users. If I change permissions for Users, or add
my own account to the permissions list, Full control is not offered in
the dialog.

I'll log on as root and see what I can see.

As root, I was able to give Users full control; Administrator users
already had it.

I rebooted and made sure the key got the new permission before checking
the TWAIN behavior. There was no change in the TWAIN behavior.


I don't have anything here, to reproduce a TWAIN setup with.
Try Process Monitor from Sysinternals.com, do a trace without
any filter entries, and have a look at what is happening.
Maybe you'll get a hint that way.

In the file menu of ProcMon, you untick the capture item, to
stop tracing. And then you can go through the log, looking
for anything relevant. You would go through the motions
of trying to access the TWAIN device, while ProcMon is
capturing, then when it fails, you can go back to ProcMon
and stop the capturing.

Paul

OK, it's been a long time! I apologize for that.

Since I wasn't scanning at the moment, the scanner wasn't on my priority
list, but finally I remembered to install & use the Proc Monitor, almost
3 weeks after I downloaded it :-)

It was hard (half kidding): it took me a whole half hour, partly because
of figuring out how to use the program & partly because of the huge
amount of data it captures. I used the folder view to find an
appropriate search term, and a filter to take advantage of it to winnow
the view down to only 1600 or 1700 lines.

I finally found FILE NAME CONFLICT or something like that related to
Twain, referring to two files in my AppData\Local\Temp folder. I killed
them, and voilà! I can now scan without running as Admin.

The files were TWAIN.LOG and Twain001.Mtx, and they apparently served as
locks to prevent simultaneous access to Twain from (something).

Many thanks, Paul!

--
Gene E. Bloch (Stumbling Bloch)