On Mon, 02 Apr 2018 17:58:14 -0400, Paul
wrote:

snipped for brevity


Uninstall Bit Defender, not just a file.

While Windows is running, not only does it have permissions
(like TrustedInstaller), but it also has Windows File Protection,
to prevent malware from messing around. Of course, real malware
doesn't particularly care about WFP, but WFP is a great way
to prevent *users* from messing around.

Your advice is a good one, to simply remove Bit Defender
as part of an experiment, to see if it's the root cause.

If I was doing this, for safety I would back up C: first,
then remove BitDefender. I could then restore my perfectly
working BitDefender + Windows installation later, from
that backup, if I didn't like the mess I'd made for myself.

Just yesterday, I "walked out of a mess" by using a 100GB
backup of C: , so I regularly use this backup technique when I know
an experiment will lead to grief. I had made extensive changes
to a multitude of network settings, and I "didn't have to
be careful, because I had a backup".

AV companies regularly provide "uninstall/cleaner tools"
for their products. Going to Programs and Features and
uninstalling, is the first step. The "cleaner" can remove
AV services which are "difficult" to remove. Some AV companies
make this kind of utility harder to find than others.
And note, that the instructions for usage are important.
A cleaner can either be run, to do the entire job. Or
a cleaner can be intended to *only* be run after the
Programs and Features removal has been attempted.
You need to download the cleaner, but also carefully
read the instructions for usage.

https://www.bitdefender.com/uninstall/

Paul

Turns out their Uninstall is for Paid or Trial version. I have the
Free version.

So I'll follow your strategy but use the Control Panel Uninstall
feature and see how it goes. I'll use Windows Explorer and RegEdit to
look for leftover stuff to delete. Startup is invoked with a
scheduled task so I'll look there too.

I should have time tomorrow.

Thanks,

DC