Thunderbird Quick Filter suddenly stopped working
FIXED: I've had this problem in the past with select IMAP folders not accurately showing items using the quick filter tool (items would show up in the global thunderbird search though).
- Right-click folder | Repair Folder
- File menu | Compact Folders
From there, you should see in Activity manager (tools menu | Activity Manager) the folder probably re-downloaded, and reindexing of all the messages will occur. After that, your Quick Filter should accurately reflect items.
It had been a while since I'd done maintenance on thunderbirds folder structure :)
Since this problem occurred I seem to have found the answer. At a certain point, when the mailbox reaches ~25,000 messages, the filter (as described above) stops working. Once I deleted some of the messages it started working again, and once I got new messages that got the inbox message count "above the limit", it stopped working.
I tried compacting the folders as described by David T, but that didn't really help.
Right now the only handling seems to be to not accumulate too many messages.