Hello, My client has a specific problem with Thunderbird, when he does something with mail for example moving it to a certain folder or deleting one, all emails disappear, then when he restart the app all emails show up again and that mail is not deleted/moved, I tried all of the suggestions in the attachment and problem sometimes disappear for 1-2hrs but always occurs again. Also Thunderbird generated 50+ Inbox folders by itself and it keeps making them all alone. I assume the problem is with some corrupted file but his thunderbird backup is about 50GB and he needs it all to be imported. It really drives me crazy. Thank you in advance for your support, Hope we will solve this issue.