There are a couple of reasons this "Freeze" can happen...
1) If you are watching systems over a network, each one of them will be given up to 60 seconds to respond. This makes it look like EM is frozen because it is totally focused on trying to establish a connection. After 60 seconds it will give up and mark that connection as bad and move to the next one. Obviously if there are several bad connections this can take a while before EM will show up and start acting normal.
2) If you have EM check for updates or auto update your stats and the server exists but isn't responding, EM will freeze on "some" systems. I rarely see this happen, but some do. I don't know what makes one computer freeze up when another doesn't. In order to solve this problem I have written some new code that will be in the next release version (2.0.2) I am hoping will cancel the connection if the server hasn't responded withing 30 seconds. That should be long enough to know that something has gone wrong.
Other than those two things, EM should not just freeze out of the blue. I run it 24/7 on my system monitoring 7 boxes and it is very, very rare to have a problem. Thanks to bug reports from everyone, and the fact I run it 24/7, the program is fairly stable for a windows app.
