Vista users seem to be experiencing problems with Windows Live Messenger 8.1. From what I can gather, it is attributable to two things; DEP and Adobe Flash.

So, what to do next.. Mary Jo Foley of ZDNet has this on her website..  

The Microsoft-suggested workaround:

1. Uninstall Flash Player (Click Start->Control Panel->Uninstall a Program, then select Flash Player)

2. Close Windows Live Messenger and any other programs that use Flash

3. Open Adobe public Flash Player beta site (

4. Click “Download Installer for Windows Active X” to install

It’s the Adobe Flash player causing the crashes, concurred Robert McLaws of fame. “If you’re on Vista, you have to install the Adobe Flash beta. (Then), it (WLM 8.1) will still crash on exit every once in a while, but nowhere near as bad as it used to.”

The other option is to uninstall Live Messenger 8.1, and revert back to version 8.0, which can be downloaded from here.