Thunderbird folder allocation

I've got a bunch of email accounts running in thunderbird at any given time, and try to keep my emails nicely organized. Turns out, Thunderbird doesn't account for this (at least not with IMAP accounts) when compacting your folders.

Try manually compacting your folders (notably the "all mail" folder does not get compacted) on an individual basis. Doing this trimmed my thunderbird profile from 320MB to 76.1MB. YMMV.

Thunderbird, from what I can tell, only compacts "Inbox" on its own.

Currently I've just one (POP) email account in Thunderbird. Even after compacting my profile folder (under %AppData%\Roaming\Thunderbird\Profiles) takes 600MB.

What do you mean by "compacting folders manually"? Compacting all folders individually in Thunderbird (right-click -> compact for each folder)? I've done that, too.

Edit.

I've ~3000 mails and many of them contain attachments. :D

Ah, the joys of desktop email.

This is just a guess (one of my habits when stuck for an answer).

Perhaps folders may be considered "In Use" and not available for compacting whilst the Internet is actively (or potentially immediately actively) updating their contents.

The consequences and work-around for POP and IMAP could differ.

I've ~3000 mails and many of them contain attachments. :D

Sounds like that'll do it. The only emails I keep saved are invoices and product keys, so I have relatively few, all without attachments.

This is just a guess (one of my habits when stuck for an answer).

Perhaps folders may be considered "In Use" and not available for compacting whilst the Internet is actively (or potentially immediately actively) updating their contents.

The consequences and work-around for POP and IMAP could differ.

It seems the default behavior is to only compact the "Inbox" folder and not any of its sub folders.