What is the manufacturer and the model of your mouse? Is it connected wirelessly, via USB or via PS/2-interface?

Is a proprietary (manufacturer-specific) driver installed for your mouse? If you have admin rights on your PC at work, you could try to uninstall that driver, because it might be an incompatibility issue. Windows 7 supports most of the input devices out of the box. Be sure to have the install files for that driver available before uninstalling it, in case you must reinstall it.

Do you maybe have installed a FF-addon which currupts correct behaviour? (prevent a list of addons, if possible.)

Try also the following: Enter "about:config" in the address bar and confirm the warning. Enter "mouswheel" in the textbox entitled "Filter". Check, if all listed have the default (standard) value. Standard values are not highlighted, modified values are formatted bold. You reset a value to the default by using the right mouse button. Some settings might only take affect after restarting FF.

Check out this help topic: http://support.mozilla.com/en-US/kb/Cannot%20scroll%20with%20mouse%20wheel%20or%20touchpad

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the add-ons is causing the problem (switch to the DEFAULT theme: Tools > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.

See:

• Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

I just got a new work PC. It's a Lenovo ThinkCentre 0809. Looks to me like the keyboard and mouse are what came with the machine. The mouse is a Lenovo wired, optical mouse, M-UAE119. The scrollwheel is working in all programs but Firefox. I have the latest Firefox installed. I have tried the troubleshooting suggestions. I tried installing the latest driver for my mouse and I messed with my config settings and I tried disabling a bunch of add-ons and then tried running Firefox in safe mode. No luck. I can click the scroll wheel and get that other mode of scrolling to work and that usually gets the regular scrolling to work too, but I'd rather not have to do that all the time to get my scroll wheel to work.

1. type "about:config" in the address bar
2. acknowledge the warning
3. type "emulate" in the Filter
4. set the value of "mousewheel.emulate_at_wm_scroll" to true by doubleclicking it
5. tell me if it works

@Hermes: I think that worked!

For me, this seems to be related to having PDFs open in the browser. If I go to the PDF and zoom in and out and close it, I can usually get it working again.

Thanks for your help, Hermes, but it still doesn't work. And again, just Firefox.

That about:config "fix" doesn't work. Or rather it works temporarily but then the problem comes back. I can make it scroll by clicking the scroll button twice. The first click brings up the little arrows in a circle widget, the second click removes that and suddenly the scroll wheel works. I shouldn't have to double click on a page to scroll it though. What gives Mozilla?

Thank you, Hermes, that worked perfectly.

Not working for me for the first time. I have closed the Firefox with "Firefox -> Exit" after changing the config, and then wait for the process to die (since I tried re-start Firefox but it said it was still running). Then I started it again and clicked "Restore Last Session", found it was not working. Then I re-checked the config has been set and restarted Firefox with at the same way, but opening a new tab to browse yahoo! just before clicking restore session. IT WORKS!!! Thanks!!!

about:config did not work for me.

I restart FF without Add-ons (Help->Restart with Add-ons disabled). Do not change your configuration during restart! A second "normal" restart and it still works. I don't know how long it will work.

Tried it but nothin doin'.

When I typed "emulate" into the filter, the screen went blank. Apparently, the line doesn't exist. So this didn't work for me.

It's now July 7, 2011 and the scroll wheel on my mouse is still not working with Firefox. I have tried all the suggestions above.

I fixed my problem! I was messing around in msconfig to turn off Lync from my Startup list and noticed something called Mouse Suite 98 was in my Startup. I did a quick google check and learned I could remove it without doing any harm. And voila! My scrollwheel is working properly with Firefox, finally! Hope this helps someone out there.

I had a similar problem with my scroll wheel not working reliably after upgrading Firefox recently. It turned out to be the IETab extension causing the problem for me. I disabled the addon and the scrollwheel began working again.