User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:61.0) Gecko/20100101 Firefox/61.0 Build ID: 20180807170231 Steps to reproduce: Deleted messages from mailbox. When I reached the preset 20 Mb level, got dialog box to compact mailboxes. Actual results: Compacting appeared normal with display of memory saved after compact shown. Deleted a few more messages and got the compact mailbox dialog box with a predicted memory saving of a little larger than last dialog box. Let compacting take place where all appeared normal. Deleted a few more messages and got compact dialog box with memory savings larger than last time. Expected results: Compacting should compact the mailboxes and report back the memory saved. It should not show compact dialog box until selected limit is again reached. It is as if the compacting does not delete the selected messages that were selected for deletion.

Thank you for reporting this. It is being covered in bug 1260698. Unrelated question - did you intentionally update to version 60 via download from website? Or, did you get updated automatically?

Ignore the unrelated question - I was thinking of another bug report.