User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.1) Gecko/20061204 Firefox/2.0.0.1 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.1) Gecko/20061204 Firefox/2.0.0.1 I recently upgraded to Thunderbird 1.5.0.9. Since then, I have realized that Thunderbird will slowly increase it's memory usage until everything is exhausted in less than a day. I have to kill it off when the usage reaches 1.5GB of RAM. This problem did not appear until I started using 1.5.0.9. My Inbox has about 350 messages in it. Reproducible: Always Steps to Reproduce: 1. start thunderbird 2. wait a few hours 3. open Windows Task Manager and look at the memory usage for each process.

Patrick, what happens when you start in safe mode?

Same thing. I restarted Tbird in safe mode. After a few hours, the memory usage gets up to about 1.4GB. It doesn't crash but it slows everything down. FYI, my machine is a Thinkpad T60p w/ 3GB or RAM.

I have the same problem with Thunder 1.5.0.9 under Windows XP SP2. Version 1.5.0.8 worked perfectly. Now I have 1Gb of RAM and each hour have to close Thunderbird because of usage reach up to 1Gb.

I shut off Google desktop search and restarted TB. There was no change. The memory inched up to 1.4GB before I killed it off.

very likely a dupe of bug 346361.