Excessive CPU usage in FireFox Beta 3

With the latest version of Ubuntu comes also the latest beta version of Firefox (which is, at time of writing, version FF 3 beta 5). Now, this version is still a beta version, which means that it may contain bugs. In fact, it contains 1 serious bug, being the fact that the CPU gets a 100% usage load when you use Firefox.

The problem lies in the security-settings of Firefox. In a default configuration, Firefox checks if you are accessing a suspected attack site. If you have enabled it, it even checks if you’re accessing a phishing site (a forgery site, as it is called). When you access a site containing Javascript, Firefox will go nuts, and this will eventually result in a high processor load – which is never good.

Now, there is a very simple workaround, given the fact that you will have to turn off the security settings. Go about it as follows:

(1) in Firefox, go to your preferences (Edit -> Preferences). Go to the Security-tab, and uncheck following options:

- Tell me if the site I’m visiting is a suspected attack site
- Tell me if the site I’m visiting is a suspected forgery site

Then, close down Firefox completely.

(2) go to your Home Folder (Places -> Home Folder). Make sure you’re able to view hidden files and folders (by pressing either Ctrl+H, or go to View -> Show Hidden Files).

(3) navigate to /home/(username)/.mozilla/firefox/xxxxxxxx.default/

The folder may vary, but the name always ends in .default .

(4) delete the file urlclassifier3.sqlite and (if present) the file urlclassifier3.sqlite-journal.

(5) restart Firefox. The file urlclassifier3.sqlite will be recreated, but this time, it will stay about 9 kB, without getting any bigger.

Note: you have to repeat this for every user account!

Enjoy your Firefox v3!