I ran into this problem with nVision a little while ago. nVision processes were going to error status on the process scheduler. A quick glance at the logs made it look like either the process was crashing or not starting at all. I logged into the Windows Process Scheduler server to take a look at Excel. Logging in as the service account that is used to run our process scheduler I looked at task manager and saw two copies of Excel which had been running, however no jobs had been run for quite a while. I killed the processes and tried to start Excel by hand and began to wait. Several minutes later Excel popped up a window stating it was starting in safe mode, probably because I killed the processes I assumed. Once it started I went ahead and closed it cleanly and tried again. Again about four minutes later it finally opened. However, this time it opened with the recover lost files pane open and displayed what I would estimate was 1500+ recovered files. I closed the pane not saving any and removing them which took some more time. Eventually I was able to shutdown Excel again. The next time I opened it, it started right up in a second. I proceeded to disable the AutoRecover feature in the Save settings in Excel Options (for 2007).
I’m not sure what caused them to show up, or if they were there all along and just finally got to the point where Excel took too long to open. Like many, I inherited this environment, but now I have one more thing to add to my environment assessment checklist for the next time.