So I'm about to start development work today and I crank up remote desktop to access the virtual machine on my development server. And it crashes. So I try accessing other virtual and real machines. And it keeps crashing. So I disable anti-virus and close everything possible. Keeps crashing. If you're interested, this is the error:
Faulting application mstsc.exe, version 6.0.6000.16386, time stamp 0x4549b425, faulting module ntdll.dll, version 6.0.6000.16386, time stamp 0x4549bdc9, exception code 0x80000003, fault offset 0x00042ea8, process id 0xd28, application start time 0x01c8ac7a33dfff9c.
So I do some Google searches and don't find much of relevance. But I do try disabling UAC (I'm running Vista Business). Still crashes. Then I try to remember the last time it worked and what I've installed since then. And I did install something interesting yesterday, namely the DirectX SDK (March 2008). So I do a system restore to the point I saved before I installed the SDK. Still crashes. So I undo the restore, which fails... But I'm not ready to give up yet. So I uninstall the SDK. And remote desktop starts working again.
So, it appears that installing the DirectX SDK hosed remote desktop on my Vista Business machine. Don't understand why, but there you go.