Without any good reason, eM mail started _moving_ thousands of mails from “All mail” to “Trash”. Almost my whole mail history disappeared just before my eyes without any explanation or other means of stopping than killing the process!
I have been able to move the “Trash” mail back to my “Inbox” using the gmail web interface, but now everything is just messed up - all the real trash came along. Years of deleting and sorting mail are ruined!