"move to" a folder does not show up in the folder.
Call the destination folder "A". Moving an email from the inbox to A does not show up in A. If I try again I am told that the operation is in progress - 5, 10 minutes later it is still in progress. There is no problem moving the same email from the inbox to folders B, C, etc. In addition most, but not all, of my earlier contents in folder A have disappeared.
Todas as respostas (1)
sounds to me like A is corrupt. copy out of it everything you can and then right click it and compact. This will clear the corruption, and in the process delete probably everything in the folder.
If that does not work, it may bee that the disk location that the file occupies is actually the issue. Delete the folder from Thunderbird. (removing a disk file which this does should not result in error as it does not access the actual file.)
Use Windows tools to scan the disk for errors (will require a reboot and take a long time. It is finds errors I have seen them take hours. Overnight is a good time)
Reopen Thunderbird and recreate your folder.