Looks like no one took me up on my offer of finding more examples, but I recently ran into one:
DirXML Log Event -------------------
Message: Code(-9075) Shutting down because DirXML engine evaluation period has expired.
If the license on the installation has expired, then you cannot start a driver either. In this case, we had started with the 90 day trial license under IDM 3.01, then installed the real license and all was good.
Then we updated to IDM 3.5.1 and forgot to put in the 3.5.1 license, and after 90 days we started getting this error.