Does anyone here use Malwarebytes to scan files in Windows Explorer?

I Scan every file I Download with Avast!, SuperAntiSpyware (SAS) and
Malwarebytes (Free) 2.0.2.1012 (MWB) before I will install them in my
XP Limited Users Account.

When I scan files from Windows Explorer (WE), Avast! and SAS work as
they always have, but MWB recently seems like it will not scan files
for me in WE.

I right click on a group of files and select
"Scan with Malwarebytes Anti-Malware"
and see the MWB program start but it never starts scanning the files.
I've waited over 20 Minutes to give it time to decide what to do but it
never starts the scanning process.

Yesterday I opened the Admin account and tried using MWB to scan some
files and it never started the scan, but I tried scanning one file and
it did complete the scan.

I tried scanning the same group of files I tried to scan earlier and it
never started the scan that time either.

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