We had a concerning scenario come up with self-hosted workflow regarding an unidentified object. Only a re-install could resolve the problem.
Build: 12.0.2508.3111 (deployed on the 5th of this month about a week before the problem started)
Monday morning they noticed no workflows were kicking off.
Looking over the history we see the last workflow to run was Friday and first thing at 1am on Saturday morning, after a system reboot, the WF Service posted many event errors to the Event Log which simply said
The object must have it's connection set before it can be used
We double checked the standard configurations and restarted both WF and Subscriber service, then the entire OS to confirm no new errors were being posted to any of the WF Admin Console logs or the Event Viewer. Absolutely nothing was posted to a log in WF Admin console and the event viewer just had one informative post regarding the license being good.
The subscriber trace would not load any events when opened (even from before Friday), we could only see events in the live event viewer as we created documents. The trace log remained empty each time we tried to view it.
The last event time in the repository tab was from the year 0001
We tried removing the repository registration and deleting the subscriber. Then setting it all up again, but no changes.
We could publish and run workflows manually.
We could never find the object which needed it's connection set because the error did not specify what the object was and it was not something intuitive.
This morning we just uninstalled workflow entirely and performed a new install. Immediately after all previous workflows from the last few days ran and new instances continue to work normally. The subscriber trace is currently showing new actions but still refuses to show any actions from history and I don't know where the historical events disappeared to or where to search for them in the database.
This is the first I have been unable to access the subscriber trace entirely, I have only had missing events before but not a blank log. I am posting this in case anyone else runs into the same thing to get feedback.