Ok, I posted this to the newsgroup (news.stardock.com) with no response, there seems to be a lot of activity here so I'll give it a go.
Here is the text from that message...
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I'm running Keepsafe 0.96[b].002 and when keepsafe loads on start, the
firefox.exe and thunderbird.exe processes do not properly terminate. The
windows will close, but Task Manager has them still in memory (and
taking up memory). If I try to shut down Windows without manually
terminating the processes I get an error saying that
"XPCOM:EventReceiver" is not shutting down.
If I disable keepsafe.exe in msconfig, all works well again.
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Ok, now obviously keepsafe is doing something that these guys don't like. I've not really had a good opportunity to play with it yet and it might be fixed by excluding things like the profile directory. I will have to further investigate.