The fix https://support.mozilla.org/en-US/kb/cannot-delete-messages did not work for me. When deleting obsolete emails I noticed that one recent message from CV-Library (as of 06 Feb 2018) cannot be deleted. The green bar of progress at the bottom left is practically full showing that the deleting is in progress but nothing happens. This problem brings the other one - the Inbox folder cannot be compacted. The error message says: "The folder 'Inbox' 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, then try again." Any idea how to delete a massage apart from that described above? I am using Thunderbird Portable v.52.6.0 (32-bit). Win 10 (64-bit)