Try "Reset all user preferences to Firefox defaults" on the Safe mode start window.

See also:

• http://kb.mozillazine.org/Preferences_not_saved

Hey there, I already tried safe mode. I also tried making a completely new profile. Since that didn't work, I completely removed Firefox with AppZapper.

This is unrelated, but since it's a mouse issue, I tried resetting the mouse by plugging a USB one in then unplugging it.

I'm having this same problem. It's not just websites that don't have the :hover - the problem is the same in my bookmarks toolbar (nothing is highlighted when hovering over bookmarks)

I am on Mac OS X 10.6.6 and am using Firefox 4.

I can make the hovers work again properly if I hold down my mouse button (eg. if I click and hold on the Firefox 'Home' button and then move the mouse onto the page all of the hovers will work as long as I keep the mouse button held down)

I feel a bit silly but I just restarted my computer and the hovers are working now.

A restart resolved it for me too, but it was only temporary, I didn't determine what triggered it again, but the issue immediately returned, hovers are non responsive to html (pseudo class on links), css or javascript, and cursor stays as ibeam, rather than pointer.

I have this problem as well. Restarting the computer did fix it but only temporarily. This is on 10.6.6 and 10.6.7 (installed after FF4 was).

It effects all types of hover :hover, javascript onhover, and even the web developer toolbar plugin for style information. Holding down the left mouse button will temporarily fix it but obviously highlights the text too.

Here's a quick video: http://screencast.com/t/Q30Tra3PwfIi of the issue on just a standard hover link. Notice when I click down and hold it will work but the highlighting of text also starts happening, as it should.

@bruce on Twitter if you need more details.

I tracked it down to a conflict with xScope! Quitting this app (which I always keep launched) makes the issue completely go away in FF, and launching it makes it consistently happen. Entirely reproducible. Reporting to Iconfactory now.

For others that have this, can you find another program that when launched causes this but when quit results in the issue disappearing in FF4, or do you also have xScope (by iconfactory) active while seeing this? I'm running 10.6.6.

I only have FF as a testing browser (front end developer), Safari is my main browser. I also tested with extensions disabled (Firebug + FireQuery) and they are not involved in the conflict.

Dude! Yes! That instantly worked for me too :-)

I am having the same problem on a Windows XP computer. The cursor does not change when I mouse over most links. On pages where CSS has turned off link underlining, there may be no indication that you are over a link at all, other than the URL appearing at the bottom of the page. Interestingly, the cursor turns into a hand when I mouseover the tools in the editor on this page, and the green Post Reply button, but not over any other link on the page.

A problem which may or may not be related is that the browser Back button is nonfunctional and the Back command in the context menu is grayed out.

Can people report if they have hover working with all other apps quit, but have seen hover broken, isolate another program launched with FF4 that triggers this? It might be a certain characteristic of that second app, as xScope does use hover functionality.

I've reported this to iconfactory, but thinking this may be on FireFox's side, since other's are reporting here, and for one thing, xScope is mac only. I found nothing like this over at bugzilla.mozilla.

YES! This fixes it for me to, although sad because I love xscope. If you have a bug report. If there is a link to upvote the icon factory bug let us know!

It seems it may be Firefox's bug, since it started with a new version of FF, not xScope, and a post above reported similar on Windows, where that couldn't involve xScope. I suspect a similar type of app is open when this is happening, that has to do with global screen hovering. This is why i asked for other evidence of a reproducible conflict with another program.

Here's the bug report I just submitted: https://bugzilla.mozilla.org/show_bug.cgi?id=645306

You can enter a "vote" next to "importance".

Same problem after updating to Firefox 3.6.16, on Mac OS 10.5.8. The only other program running was Growl which gets installed by Adobe CS5: http://growl.info/thirdpartyinstallations.php

Uninstalled Growl and CS5 demo, did restart, still have the mouse problem! Just posting this reply was quite an ordeal...

I've tracked down my problem too... I had a program called uPointer running (it puts a circle around my mouse pointer so I can find it) when I turn it off the hovers in firefox work and when it's on they don't - I think it must be a Firefox issue as I had no problem on the last version while using uPointer

@jamessg, great! This gives weight that it is Firefox's bug, in conflict with utilities that effects hover globally. I've added this to https://bugzilla.mozilla.org/show_bug.cgi?id=645306

To add to the weirdness here, Firefox 4 and xScope run perfectly fine together on my MacBook Air.

guys check your login items and disable all of them and logout then login, there are some interface app that does conflict with FF4, i had it fixed by this and it was app conflict issue.

Replay if it worked

We have already established that it is a conflict with utilities that effect screen hovering globally. You can vote for importance of this bug at the bugzilla bug report at: https://bugzilla.mozilla.org/show_bug.cgi?id=645306