22 October, 2007

Fixing firefox slow/high CPU issue

After installing the new version it became incredibly slow on my XP system, CPU usage shot up to 50% (i.e. took all of one of the cores), I couldn't type without swearing. Reverting as far back as 0.5 didn't help, so it had to be the settings issue.

And here's what solved it for me:

- go to C:\Documents and Settings\<your user name>\Application Data\Mozilla\Firefox\Profiles and make a copy of your running profile, just in case (copy the whole folder that is called something like <letters-numbers>.default).

- now go into that folder and remove all 0-bytes-long files called prefs-1.js, prefs-2.js and so on, and then remove all the 0-bytes-long sessionstore-1.js, sessionstore-2.js, and so on. Make sure all files you're deleting have 0 length, so that nothing important gets deleted (and if it does, that's what was the backup for!)

I suppose the problem was in sessionstore files, as I had 9999 of them, probably preventing the poor thing from creating any more.

P.S. The best tool to mess with files like that is the Far Manager.

1 comment:

Sergio Bessa said...

My Firefox also started hanging after installation.
Unfortunately this solution didn't work for me :(
In fact I only had one of each file mentioned and none was zero bytes...