RECOVERY MODEL changed on a database, no record in Default Trace I have a Log backup job running every hour via SQL Agent. This morning it failed at 3:00 AM with this error:
The statement BACKUP LOG is not allowed while the recovery model is SIMPLE.
But it ran fine at 2:00 AM. So sometime between 2 and 3, it went from FULL to SIMPLE.
My response was:

Change it back to FULL recovery
Run a FULL DATABASE BACKUP
Run the Log Backup job to make sure it would still work.
All good, no data loss.

So I got to investigating the Default Trace for events about possibly WHO might have made the change between 2 and 3. I first identified the event on Step #1 above so I knew what types of events I was looking for. Unfortunately, there is no event to say, &quot;The recovery model changed from x to y&quot;. All it has is &quot;Object: Altered&quot; for my login for the database in question, with rows for BEGIN and COMMIT.
Here's the issue: I found NOTHING in the default trace in the time span to indicate that anyone made a change to this database.
Question: How could this change have occurred and it NOT get recorded in the Default Trace? It certainly recorded the fact that I changed it back. Why not the first change?
Any help would be appreciated.
Answering my own post as I found additional information:
The trace log had no indication of Object: Altered for that database, which happened to be msdb (might be important here). In the SQL logs, I found indications that someone had applied updates, and after the first instance start-up, there was indication that msdb had an upgrade script applied then setting of SIMPLE recovery, along with creation of several synonyms.