There are a few possibilities as to why it's running slow. Let me make some suggestions:

• Check for any extensions. Some, including antivirus toolbars, Browser Highlighter, and Skype extension are known to cause delays when loading sites. See Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems.
• One or more plugins are outdated, causing Firefox to be slow when loading certain sites. Upgrade all outdated plugins by checking http://www.mozilla.com/plugincheck/.
• If you are getting delays where the status bar says "Waiting for site", make sure Firefox is fully allowed in all firewall software. See Configure firewalls so that Firefox can access the Internet

If these solutions don't help, reply back with this information:

• When exactly is Firefox slow? (When first starting, when going from page to page, when scrolling, when loading videos, when playing Flash/Java games, etc)
• When did the problem start?
• The troubleshooting information from Help->Troubleshooting information. (Open the Help menu, then click Troubleshooting Information. Press Copy all to clipboard to copy the information, then paste it in your reply.

No obviously offending extensions.

No out-of-date plug-ins (WPF disabled).

No waiting for site issues.

Clicking links that previously may have worked no longer do (e.g., support chat link). Clicking on some links in MSN don't respond for 20 minutes, then suddenly pop up on the screen.

Tried updated Firefox (although it was current). Went through troubleshooting and removed possible "read only" (box highlighted green) on profile, but change does not stick.

Need to stop Firefox.exe process to get it to respond again.

All very annoying.

Try disabling all extensions, and see if you experience the same problems. The easiest way to do this is through Firefox's built-in safe mode.

For details, see Diagnose Firefox issues using Troubleshoot Mode

I can run it fine in safe mode. But if the only way I can use it is in safemode, what is the use? I have tried removing one at a time, no. I guess I could remove 2 extensions at a time but come on... this is nonsense. And yes, all my plugins are up to date.

Firefox Safe mode is meant for diagnostic purposes and not for permanent usage.

If it does work properly in Safe-mode then disable all your extensions and then try to find which is causing it by enabling one at a time until the problem reappears.

You can use "Disable all add-ons" on the Safe mode start window to disable all extensions.

You have to close and restart Firefox after each change via "File > Exit" (Mac: "Firefox > Quit"; Linux: "File > Quit")

i have been using firefox for many years but now Im getting fed up with pages hanging.. it happens when the page is flash enabled.

i tried ie and chrome and both work properly - I just dont like them.. please fix this!

running win7 on a HP 4310s laptop brand new with all updates installed... my extensions are flashgot, xmarks, image toolbar, java, office, acrobat reader.

I tried safe-mode and it still hangs!

I also noticed that when I have two tabs open or more and I try to close firefox from task manager it will un-hang but only for a while - I cancel the closing and continue using the browser as normal... if during this time I navigate away from the flash enabled page then it continues normally. If I stay on the flash enabled page or open a new one it hangs again shortly after.

Hi, this is good advice. I will try it. Only thing I would change is to add back only half your extensions. This is a quicker way to troubleshoot instead of one at a time.

I think i found the problem on my system that is causing FF to hang and the process to only be stopped by system restart. I turned off Iobit Malware Protector and haven't had any hangs in the last 24 hours ! Any body else running Iobit having problems ?

I just tried running Firefox 6.0.1 (Mac OS 10.6.8) in Safe Mode. When it opened, it was using more memory than any other application (about 215MB). After about 5 minutes, with 5 tabs open, the main application is using 455MB and the Firefox Plugin Process is using an additional 77MB. Previously, with 8 extensions and several plugins running, FF has ballooned as high as 1.7GB. It seems to take almost every bit of unused RAM.