3.2.3 Compact causes message tabs or windows to close.It's recommended that you keep the number of messages in your inbox small, and move any you want to permanently keep to other folders/child folders.

This is usually only a problem for the inbox folder as while other folders may get very large you typically don't delete messages in them often. If you notice a message has a date of 1969 that is due to it losing the Date: header in the message.Ĭorrupt folders tend to occur when you have lots of messages in a folder, many of them are deleted, and you don't compact often enough. If you don't compact your folders regularly, performance can slow to a crawl, you can't store new messages anymore, start losing parts of messages or have deleted messages resurrected. Compacting a folder frees wasted space but the main reason to do it regularly is because it's a type of preventative maintenance. Compressing/zipping only changes how data is stored compacting changes the actual data. 'Compacting' a folder has nothing to do with compressing or zipping a file. When you empty the trash it physically removes (expunges) the messages in the Trash folder. Messages in a Trash folder aren't actually deleted messages, when you delete a message in a POP account it copies the message to the Trash folder and then deletes the original.

This is a tradeoff done to improve performance in large folders. They are not physically removed until you 'compact' the folder. Instead they are marked for deletion and hidden from view.

Even emptying the Trash does not get rid of them. When you delete messages in an email client such as Thunderbird they aren't physically deleted. This article was written for Thunderbird but also applies to Mozilla Suite / SeaMonkey (though some menu sequences may differ).

Mozbackup thunderbird