Thunderbird 128.5.2esr (32-bit) Odd problem in that just one folder was being identified as not being able to be compacted because of Disk Space....not true, plenty of space as I keep it regularly cleaned. I can clear the issue by making another folder of a different name, copying all messages to that folder then running COMPACT on the new folder and nothing is amiss. Run it on the original problem folder and no issues. Delete the original folder and create another with the same old name and transfer the messages to the now new originally named folder. Delete the TEMP folder. Then run a COMPACT on the problem folder and no issues. Then run compact on the whole message tree and sure enough the COMPACT issue has now moved to a different folder. I suspect you could chase this thing till the cows come home but won't resolve, just moves it from folder to folder. Now I could just kill Thunderbird and reinstall but this is intriging. Not sure if that would help. Ran TROUBLESHOOT MODE clean with out the only extension I use and no change. Stumped. Thanks!