Hello In my Thunderbird (Windows 10), undated to last release, I have several mailboxes. For one mailbox (and only this) I am getting error messages like these: "Unable to write the email to the mailbox. Make sure the file system allows you write privileges, and you have enough disk space to copy the mailbox." and "The folder ‘Inbox on .......' could not be compacted because writing to folder failed. Verify that you have enough disk space, and that you have write privileges to the file system I have deactivated the relevant functions on antivirus software (Kaspersky) and still get the error. I have also tried to start in restricted mode, still the same message. Any suggestion? best regards Bertin