Explorer Search results in 'aa' popup

[Leif]

I can't tie it down to anything consistent, but occasionally when I try and run a search in Windows Explorer, I get a popup like so:

aa.jpg

It doesn't matter what string I am searching for, this 'aa' window appears, and the search doesn't start until I click OK.

Anyone got any idea as to what is going on?

[HansV]

Is it because of Halloween?

Have you run a thorough virus/malware scan?

[Rudi]

I'm glad to say I cannot simulate that scenario.
I agree with Hans, a good scan might help.

PS: ...not halloween, but aalloween...

[Leif]

Is it because of Halloween?

Have you run a thorough virus/malware scan?

Only if Halloween runs all year for me

We're running Kaspersky Endpoint here, and various scans and AV protection do not show up anything...

[Rudi]

How about trying Malwarebytes (Anti-Malware).
It's worth a try if you haven't yet?!

[stuck]

Googling with keywords:
windows 7 search aa dialog

Turns up one hit that mentions a rootkit called AA, and idea worth investigating?

Ken