As things look like they are having issues, I would advise that you create a backup. So if you have not done one recently, then I would advise creating one before you organise folders, archive, compact etc.. just in case :) Info on Backup:

• http://kb.mozillazine.org/Profile_backup
• http://kb.mozillazine.org/IMAP_backup

It sounds like the more you use and open folders using more memory, Thunderbird starts to struggle and as time goes by, adding more emails is making things worse.

I'm not sure how you maintain your Thunderbird, but here a few pointers that may help. see which applies to your situation.

First part of organising: The Inbox folder ideally should be kept low in email numbers, I presume you are managing this with the aid of the filters and manual sorting to other folders to organise your received mail. eg: Bills, Friends, Client name etc. If no because you filter Junk, but keep good emails in Inbox, then I suggest you create some folders to help organise your mail and then move all good emails into those folders. Keep the Inbox folder for incoming mail and not as a general storage.

Second part of organising If you have emails in any folder including Sent folder, that are older then say 3 months, do you Archive those emails to prevent a build up of large folders ?

Did you set up Archive Options to Archive monthly and retain folder structure? If no then I recommend you do it. Set up Archive options first and then perform some archiving. See info:

• https://support.mozilla.org/en-US/kb/archived-messages

This will create an Archives folder in the folder Pane so you will still be able to see those emails. But it will create smaller folders which use less memory to open. The Sent folder can get large quickly and so archiving older mail will help to keep the size down - large folders use up memory when opening and moving stuff about.

After sorting folders and Archiving anything older than a couple of months

Junk and Deleted folders should be emptied on a regular basis. After emptying these folders, they should be compacted.

There is the option to set it up so that these folders are auto emptied: Deleted folder: Tools > Account Settings > Server Settings for the mail account Message storage: select to 'empty deleted folder on exit'

Junk: Tools > Account Settings > Junk Settings for the mail account Select : 'Automatically delete junk mail older than xx days' If you get a lot of junk then set the numbers of days to a few days, enough time for you to check the folder just in case a good email gets through. Otherwise a week would be a good default. Personally, I check through mine at the end of each day, then manually empty the folder and then manually compact the folder. I don't like wading through lists just for the odd email that is ok.

Remember to click on OK after making any changes in Account Settings.

All folders, but especially the Inbox (as it gets more moving, deleting etc than most folders) need to be compacted on a regular basis to remove old 'marked as deleted' mail which may be hidden from view but using up a load of space and therefore making your folder larger than you may think.

You can manually compact a single folder by right clicking on the folder and select 'compact'. This works best after you have deleted several emails.

Or you can manually compact all your folders in one go: File > Compact Folders

There is also a facility to set up auto compacting, this is useful, but do not set a too high figure. It is much better to compact more frequently than wait for ages and then use. Tools > Options >Advanced > Network & Disc Space tab Under Disc Space 'Compact all folders when it will save over '- suggest you do not make this larger than 20MB.

Info on compacting - what it does and why it is important:

• http://kb.mozillazine.org/Thunderbird_:_Tips_:_Compacting_Folders

Work through all of the above so that you know that all your folders are in good order, archived correctly and compacted to remove all old hidden 'marked as deleted' mail. Then create another backup, so that it is up to date and you have a full backup of all those Archived mail.

Once you have done this, see if the performance improves.

Other info on general performance issues:

• http://kb.mozillazine.org/Performance_-_Thunderbird

What version are you using? I'm using 24.6 and that and the 2 versions before this have had this problem. (I don't know about earlier versions since I only started using Thunderbird this year and it has behaved like this all that time.)

There are quite a few threads about it spread around a couple of forums. Recently one person said it worked for him until he started using a global inbox. So, I might try going back to individual inboxes per account. However this problem doesn't occur on a fixed schedule - for example I have at times been able to go over a month without having to restart and other times it's daily. Some people say they always see it daily at least. As a result people often do something and think they have it solved - until it comes back.

I don't know if this has had any developer interest.

I'm running the latest version; 31.1.2 but i've been using Tb for several years and never had an issue.

However, usually where people have this problem, they do not maintain their folders, compacting, archive etc as I do. I've several Pop mail accounts, but do not use Global Inbox (Local folders).

Have you got a set up that is doing what I suggested in first response?

i've also use an Addon to assist me in knowing how big any folder has got, so reminding me to Archive and compact folders. This is the addon: Extra folder columns:

• https://addons.mozilla.org/en-US/thunderbird/addon/extra-folder-columns/

I've only enabled the Size column so that it doesn't take up too much space in the Folder Pane.

Sorry I meant what version is PJVoisine using. While I have seen nothing in the release notes about fixing this, it would be nice to know whether it persists in newer versions.