Unknown column Sprolf in where clause

[Error]

I'd guess by the error message that this is could be helpful:

Judging by your join date I would presume that what you're seeing is the infamous "1054 - Unknown column 'Guest' in 'where clause'" MySQL bug that we got after the IPB -> MyBB transition in late 2012. If that is the case, you can fix it yourself by following the instructions in the post quoted below.

Have a look at this thread, and particularily my last post in it.

EDIT:
What you need to do is:
1. Download your old messages, if you want to keep them
2. Empty all of your PM folders.

That'll fix it.

PS: Welcome back, by the way!

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