[]I have a feeling what has happened is that you've got private messages that are attached (sent from) a user that has been deleted.[/]I don't think that can be the problem since I only deleted about 5 users in the board's existance.

My problem is that right after the upgrade the database size is consistent with the amount of private messages I did not delete before the upgrade, indicating they are still in the database somewhere, but none of these pre-upgrade private messages are visible to their recievers.

The w3t_Messages info shows 7987 rows and 6.31 MB data length. The result of MAX(M_Number) is 67210, MIN(M_Number) is 57850, which could be correct, assuming I deleted all messages before number 57850, and about 9000 messages have been deleted by their recievers.

It feels to me as if the reference to the recievers of the messages has been lost, not the info (senderid) of the sender.

Rick, it would be nice to give my users their old messages back, but if you think this is not solvable it is not much of a problem to me. I'll simply delete all pre-upgrade messages if nothing helps.