Saturday, January 10, 2009

Excessive CPU usage with Thunderbird

Recently I noticed that even when Thunderbird is idle, it seems to be eating up a lot of my CPU. When I first start up the program it is fine, but within an hour or two it would be using up ~10.2% of my CPU, and would remain that way until I quit the program. I started hunting around on the internet, and found the issue on a Unix/Linux forum here. It turns out that if you set your new mail notification sound to be something other than the default system sound, Thunderbird cannot handle it. Whatever subroutine handles the notification plays the sound just fine, but then it hangs and does not close. I tested this out myself, by first setting the notification sound to the default sound and restarting Thunderbird (the CPU usage was already high). I then sent a test message to one of my email accounts. The CPU usage went up slightly as the message came through, the system sound went off, and then Thunderbird went back to idle, using 0.0% of my CPU. I then set the notification sound to a non-system default ("Use the following sound file:") and sent another test message. The CPU usage shot up when the sound played and stayed around 10.2%. I waited for a few minutes and it never dropped back down. I had definitely found the culprit. Apparently Thunderbird is aware of the issue, and the fix will be included in the next version of Thunderbird (version 3).


  1. Noticed the same thing with the CPU here.

  2. Strangely enough this is still a problem in 2015. Thunderbird versio 38 :)

    Thanks, for the tip!