Firefox has recently become unbelievably slow and laggy

[Humes fork]

Since a few months back, Firefox has become incredibly slow and laggy. To open a website (any website really, even Wikipedia) seems to be such a burden for it. If I play a Youtube clip it will frequently stop it when loading a new site.

How to fix this? I tried SpeedyFox, but it only fixes the problem for a few hours, or a day at most. Any other way to fix it? A more permanent way?

 

[lauwersw]

Try running without addons for a while and see how that works out. The easiest way to do that is via the Help menu, option "Restart with Add-ons Disabled..."

If that improves the situation, restart in normal mode and disable all your add-ons manually. Enable them one by one until you find the guilty one.

If that doesn't work or you don't have any add-ons, try creating a new profile and see how that changes the situation.

Further info here: https://support.mozilla.org/en-US/kb/troubleshoot-and-diagnose-firefox-problems

 

[Soapy Sam]

When did you dump the browser cache last?

 

[BrianH]

I use this add-on to give me a lazy man's icon (and a few basic customization options) to clear the cache on a regular basis: EmptyCacheButton

Keep in mind that it is going to take a while for it to clear everything the first time you do it, it may seem like Firefox is hung.

 

[nois forme]

Since a few months back, Firefox has become incredibly slow and laggy.

No idea if this is your issue, but the last Flash Player update I grabbed ruined my FF. The version I had at the time was '1.9.900.170', so whatever immediately followed that broke my FF. Everything got quite laggy (esp. that related to Flash obviously - YouTube was bad). I had to use their tool to uninstall, and returned to the previous version which has worked fine since. Good luck.

 

[Floyt]

When did you dump the browser cache last?

Well, interesting. I thought that would be cleared out in general temp file sweeps, which I do regularly. But apparently FF keeps a tight hold on its own cache. Mine was 350Mb - now 700Kb (and yes, it did freeze for a few minutes while clearing).

 

[Safe-Keeper]

I have the same problem, and often Flash seems to be the issue. "Crashing" Flash when FF hangs often makes it start running normally.

Will try to clear the cache with the "Empty Cache Button", Brian. Thanks for the advice.

 

[Floyt]

(You can just clear the cache from Tools -> Options -> Advanced -> Networks; no need to get an AddOn)

 

[Axiom_Blade]

Sounds like you need to reset Firefox. This will clean all of the cruft out of your installation, while preserving your cache, bookmarks, etc. Go to Help > Troubleshooting Information. Click the button in the box on the right side side of the page that says "Reset Firefox".