I have had two instances now where the POP connector to exchange 2003 failed to deliver mail. When digging around i noticed that the imbservice.exe is stuck at "stopping" in task manager. Once the process is terminated it can be restarted successfully. A few weeks later the problem will appear again. Anyone know of a trigger for this behavior?

I assume this is SBS? If so, please ask in the SBS Forums for a better response: http://social.technet.microsoft.com/Forums/en/smallbusinessserver/threads