Quick note in case I need again some day. The team recently moved all the user databases for a monitoring instance to new hardware and it basically went well. Immediately afterward there were a number of error messages in the log about a missing user defined error message. Minus 5 points for not moving MSDB. We had the “old” MSDB of course, but we found this fix which took care of the problem by just adding back the error messages. Problem fixed, sorta. Turns out it was then failing differently and the new error wasn’t in the SQL log. Once I heard “service broker” it was an easy fix:

alter database ABC SET ENABLE_BROKER WITH ROLLBACK IMMEDIATE;
alter database ABC SET TRUSTWORTHY ON;

There are a handful of lessons there, the least of which is about SCOM.