I'm running Zeus 3.97s on Windows 7 64bit and randomly but at least once a day Zeus will lock up and Windows will report it as not responding and force quit.
There are at least two things found in Zeus that are run in the background.
The first is the tag rebuild of the current workspace and the second is a check of the file status, which happens every 3/4 of a second.
If any of these tasks take a long time then you will see the 'not responding' status from Windows.
In normal operation I do not see this, but I have seen it happen on a machine running several background builds and thus having that build consume most of the free CPU cycles.
I have also seen this when a massive workspace was loaded into Zeus and it was doing a tags update.
I have also seen this for a network file (i.e. \\some server\some folder\network file.txt) and Zeus was having trouble connecting to the network to get the file status.
Naturally for this case, while Zeus is showing the symptoms, the real problem is the slow network.
If you have a large workspace loaded, try using the Tags, Rebuild menu which will rebuild the tags database (which might be corrupt).
it as not responding and force quit.
In all the above cases, you should not have to force a quit, but instead just wait as Zeus should eventually return.
The first time I ran into the file network issue I though Zeus had crashed, but after waiting one minute (i.e. the timeout period for the network) Zeus came back to life.
But if you are seeing the network problem, make sure you close the network file otherwise the same thing is bound to happen.