Do you have separate users on the computer that Firefox is being updated by another instance? If so, check to make sure they aren't in the middle of updating Firefox.

Have a great day!!

Jon

Hello, in the past the issue was caused by the Delicious Bookmarks extension, if you have try to disable it and check it again, otherwise, try Firefox Safe Mode to see if the problem goes away. Firefox Safe Mode is a troubleshooting mode that temporarily turns off hardware acceleration, resets some settings, and disables add-ons (extensions and themes).

If Firefox is open, you can restart in Firefox Safe Mode from the Help menu:

• Click the menu button , click Help and select Restart with Add-ons Disabled.

When the Firefox Safe Mode window appears, select "Start in Safe Mode".

If the issue is not present in Firefox Safe Mode, your problem is probably caused by an extension, theme, or hardware acceleration. Please follow the steps in the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article to find the cause.

To exit Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.

thank you

Your user agent shows that you run Firefox in compatibility mode for Windows 98 (NT 4.10).

Make sure that you do not run Firefox in compatibility mode. You can open the Properties of the Firefox desktop shortcut via the right-click context menu and check the "Compatibility" tab. Make sure that all items are deselected in the "Compatibility" tab of the Properties window.

Thanks jon. I did not have that exact problem. I found two users in my mozilla and deleted one. It worked

Willy did you see comment above yours as you seem to be running Firefox in compatibility mode. This can cause issues.