I'm using Nebula 128.5esr 64-bit on my Mac. Some emails in inbox does not opening; even in Troubleshooting mode... cannot be deleted / moved etc... even I restart Thunderbird many times result is same... recently it happened again and I was able to remove by chance (I tried moved, delete, restart etc..). but then some folders are got empty and hundreds of emails are lost... I can only mark as read - unread only.