I left it over night and it’s the same this morning. I thought that it just needed time to compact the folder, or re-index etc… but it’s been days. The CPU and memory are both going crazy and have been since I copied a large section of an IMAP folder (I was running out of space on the IMAP server) to a local folder. I looked, and sure enough, the setting was wrong. Thanks, Wayne!Ĭlearly, there is something else going on with my Thunderbird. Perhaps extending the timeout so much introduces a slight risk of corruption if Thunderbird (or your computer) crashes, but it’s a price I’m willing to pay for a nice quiet laptop.Įdit : Wayne from the Thunderbird development community added a comment below with more guidance. 300000ms), and re-opening them is very expensive if you have large folders full of crapimportant messages. Mine dropped from 60-100% down to <1%.Īccording to that bug report, Thunderbird closes its database after five minutes of inactivity (i.e. That’s it! You don’t have to restart Thunderbird to activate the change, and you should see an immediate improvement in its CPU usage.

Check the number of zeros you have if you only have 300000, that could be causing your CPU problems. According to that bug report, the correct value is 30000000. Type idle into the search box, and look for mail.db.idle_limit. You’ll then be presented with the configuration editor. There will be a dire warning, which you can safely ignore. Click the Advanced tab at the top, then choose Config Editor. Perhaps they’ll fix this by default eventually, but for now here’s a quick step-by-step on how to fix the problem yourself.įrom the Edit menu, select Preferences (for later versions, select Options from the Tools menu). It makes Thunderbird 17.0.2 much more gentle on the CPU, and according to the report, should work from version 15 onwards. Finally I found this bug report which has a working solution. A bit of poking reveals that it’s a real CPU hog if you have large mail folders (and I never delete anything!). It’s always served me well, but recently I’ve noticed that my laptop’s battery life is abysmal when it’s running.

Mozilla thunderbird mail tweak