From MozillaZine Knowledge Base

This article was written for Thunderbird but also applies to Mozilla Suite / SeaMonkey (though some menu sequences may differ).

Thunderbird creates a temporary file called "nstmp" when it's compacting a folder. If Thunderbird is interrupted during the compacting, it will abort, and the temporary file will not be deleted. If the problem occurs multiple times, you'll see numbered files (nstmp1, nstmp2, etc.).

Shutting the program down during the compacting process, whether intentionally or due to a crash, will interrupt the process. Receiving a new message in the folder you're compacting will also interrupt the process. For this reason, it's recommended that you choose to work offline ("File -> Offline -> Work Offline") before you compact a folder if you run into this problem.

Check to see which folder the nstmp folder is duplicating, and check that the original folder is okay (e.g. compare number of messages in "View -> Toolbars -> Status Bar"). If so, you can delete the nstmp folder(s) by right-clicking it and choosing "Delete Folder" (or by deleting the files in your profile).

Related problems

• Thunderbird creates the "nstmp" file in the same directory as the folder it's compacting, and then renames it. This means it's possible that you might not be able to compact a large folder because you don't have enough free disk space. If this occurs, try compacting some smaller folders one by one to free up enough space.

• A few users report a nstmp folder if they delete some messages, click "File -> Empty Trash" , the Trash folder for some unknown reason is no longer displayed and they compact the folders. This problem occurs regardless of whether they're offline or not. However, if they exit Thunderbird, restart it, and the Trash folder is displayed again in the folder pane they can compact the folder with no ill side-effects.

See also

• Compacting folders

External links

• Bug 88515 - Mysterious 'nstmp' folder reappearing