Well - that was a little adventure. I grabbed a laptop and started it in
Windows XP SP2, safe mode. I was impressed to see that the Windows Defender
Service started in safe mode, so I tried both the MSASCUI.exe gui program
and MPCMDrun.exe--the command line program that does scanning.
I did mpcmdrun.exe scan scantype 1
and then ran msascui.exe, and observed the quickscan--all that seemed to be
fine.
What was not fine was that the install indicated that the sigs had never
been updated--1.00.00.
So, after the quickscan, I restarted normally, and found it remained with
that appearance. I checked my Microsoft Update history and found that
indeed, two sets of updates had been installed successfully a few days ago.
Something is rotten... So I dropped to a command prompt and played around
with the as_sigs.msi file in \program files\windows defender. Ran it (no
change.) Did msiexec /x as_sigs.msi, followed by as_sigs.msi--and things
seemed to perk up--suddenly the UI went green and the dates and versions
were back where they should have been.
So--safe mode scanning on XP should be functional, but strange things may
happen, as well..
