Robert in CA wrote:
Success!

https://postimg.cc/SX2dFdtq

Now do the same for the 8500?

Robert

Were you using a limited user account
on the 8500 when installing ?

If so, then I might fix it the same as
the 780.

It depends on whether you were administrator,
when installing. Administrator is needed, for
the ability to "impersonate" or "elevate to"
TrustedInstaller. Only TrustedInstaller writes
to Program Files. A limited account should not
be able to write there. This is a mechanism to
make it harder for malware to get in there.

Whereas installing in AppData, there's no protection
for the materials at all. A malware doesn't even have to
be elevated to get in there.

If Seamonkey is located in Program Files or Program Files (x86),
then that would be fine for the 8500.

Check and see if it's mis-installed in the same
way or not, then make up your mind as to
the next step.

Paul