[thelist] [OT] Tip: Avoiding problems in Thunderbird

Ian Anderson ian at zstudio.co.uk
Wed Mar 8 08:38:10 CST 2006

Hi All,

having just had a distressing weekend where my email package went 
completely bananas, I thought I'd share the experience in the hope that 
others may avoid my trauma:

<tip type="Thunderbird" author="Ian Anderson">
If you use Thunderbird for any length of time, it is vitally important to:

* compact mail folders regularly
* move messages out of the Inbox into other folders religiously for 
temporary or permanent filing. You should aim to have no messages in 
your Inbox as a matter of course, for best performance.

If you do not do these two things regularly, then after some time you 
may experience things like:

* Thunderbird takes a long time to display the content of the Inbox
* the file size of the Inbox is now hundreds of MB
* Thunderbird fails to send and receive mail reliably - or at all
* Thunderbird reports grossly inaccurate number of emails in a given 
folder (especially the inbox)
* Thunderbird fails to display all the messages you know are in a given 

In my case this happened after about a year of use and about 40,000 
emails through the thing, mostly saved in mailing list and junk mail 

The reason is that all emails seem to pass through the inbox, from where 
they are copied to other folders - EVEN if "deleted" or "moved". 
Deleting or moving actually marks the data for removal, it does not 
remove it at once. It is the act of compacting a folder which actually 
deletes the data.

Having a mail file that is seven times larger than it needs to be for 
the real data in it is one issue. Another is that eventually the mail 
summary file (the .msf file in the folder beside the real mailbox file 
of the same name) become corrupt, leading to the behaviour listed above.

If things are awful, there are simple fixes described here:


It is recommended not to compact folders while Thunderbird is receiving 
email, as this can cause the very corruption you're trying to avoid.


In my case, I had to remove the .msf files, let them be rebuilt the next 
time Thunderbird launched, and then move all the messages from my Inbox 
(getting lazy about filing, there were almost a thousand in there alone) 
to a Read folder for onward filing when time permits.

Now Thunderbird is shiny and happy again. As a bonus, one thing I tried 
early on was downloading the latest version and reinstalling the 
application with TB1.5, and it now checks spelling as you type - most 

Hope this helps



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