Private Messages has been disappeared

Have you checked the "All messages" tab?

The same thing happened to me too.

I lost a lot of msgs as well :/

Yes, of course, anyway nothing.

Same problem here. At least according to the interface, my mailbox has been cleaned as a plate.

Thanks for report, we've fixed a bug that caused this problem. ~15% of PM database failed to upgrade properly. Please re-check your 'All message' tab.

Yup, right as rain. Thanks guv'

There are still a lot of pm's missing...and it's not depending on dates or something...it seems to be random

Oh, I thought they were lost, but they are only arranged differently.
Well, my eyes are not fully closed and my fingers are still typing, but I think I am already sleeping. So... good night. Let's leave for tomorrow what we can't solve now.