Is this happening when you log in as a limited user?
Microsoft developers are actively soliciting the errors.log files from users
who are seeing this error. This file on many machines is located at:
c:\program files\microsoft antispyware\errors.log
Use the subject header Error 101. You won't get a response or feedback from
this submission, but it'll help the development effort.
Here's what the program help file recommends to resolve this issue:
* If you see a dialog box with the following message after you start your
computer or when you start Microsoft Windows AntiSpyware, you need to repair
or reinstall Windows AntiSpyware. The following message can also refer to
Error 102 or Error 103:
Warning: Microsoft Windows AntiSpyware has encountered a critical error
(Error 101). Please restart Windows AntiSpyware and run the program again.
If you continue to experience this problem, please uninstall the program and
install the most recent version of Windows AntiSpyware. You can use Add or
Remove Programs in Control Panel to uninstall this version of Windows
AntiSpyware.
You can repair Windows AntiSpyware using Add or Remove Programs in Control
Panel. Click Microsoft AntiSpyware and click Change. Click Next, and then
click Update.
If you see the critical error message again, uninstall Windows AntiSpyware
and reinstall it. To do this, use Add or Remove Programs in the Windows
Control Panel. Click Microsoft AntiSpyware and click Remove. You can
reinstall Microsoft Windows AntiSpyware at
www.microsoft.com/athome/security/spyware/software.