This is happening because you are using a smart card that supports "plug-and-play" under windows 7. In this situation, Windows 7 will automatically attempt to download and install a "Card Mini Driver" for the card when it is inserted. It sounds like the Card Mini Driver that is getting installed is causing the inconsistent behavior.

The obvious workaround is to use a card that doesn't support "plug-and-play" under windows 7. If this isn't possible, you will need to post additional details about the problems you are seeing, specifically what kind of smart card are you using, and what commands are breaking after the card mini driver is installed?

Technet details on Smart Card Plug and Play in windows 7 can be found here:

http://technet.microsoft.com/en-us/library/dd979547(WS.10).aspx

answered Apr 7 '10 at 19:26