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I'm getting "The update could not be installed" even after disabling everything & restarting - why?

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  • 2 have this problem
  • 3 views
  • Last reply by br545wwst

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It also says another instance of Firefox is running, but there isn't. I'm using Windows 7, Firefox 5.0. I disabled Logitech devices, SunJava & everything else, no luck. Nothing else running except Windows stuff. This is the first time it has happened - is it a problem with Firefox?

It also says another instance of Firefox is running, but there isn't. I'm using Windows 7, Firefox 5.0. I disabled Logitech devices, SunJava & everything else, no luck. Nothing else running except Windows stuff. This is the first time it has happened - is it a problem with Firefox?

Chosen solution

If there are problems with updating then best is to download the full version and uninstall the currently installed version.

Download a fresh Firefox copy and save the file to the desktop.

  • Uninstall your current Firefox version.
  • Do not remove personal data when you uninstall the current version.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

  • It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling.

Your bookmarks and other profile data are stored elsewhere in the Firefox Profile Folder and won't be affected by a reinstall, but make sure that you do not select to remove personal data if you uninstall Firefox.


If files already have been downloaded then you need to remove the files in the updates and updates\0 folder.
You can delete active-update.xml and updates.xml as well if present.

C:\Users\<user>\AppData\Local\Mozilla\Firefox\Mozilla Firefox\updates
(%LOCALAPPDATA%\Mozilla\Firefox\Mozilla Firefox)
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Chosen Solution

If there are problems with updating then best is to download the full version and uninstall the currently installed version.

Download a fresh Firefox copy and save the file to the desktop.

  • Uninstall your current Firefox version.
  • Do not remove personal data when you uninstall the current version.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

  • It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling.

Your bookmarks and other profile data are stored elsewhere in the Firefox Profile Folder and won't be affected by a reinstall, but make sure that you do not select to remove personal data if you uninstall Firefox.


If files already have been downloaded then you need to remove the files in the updates and updates\0 folder.
You can delete active-update.xml and updates.xml as well if present.

C:\Users\<user>\AppData\Local\Mozilla\Firefox\Mozilla Firefox\updates
(%LOCALAPPDATA%\Mozilla\Firefox\Mozilla Firefox)
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When uninstalling Firefox, I saw that 4.0 was in the program list & uninstalled that (it also took 5.0). Perhaps that was the problem. Following the steps in the reply got me on 6.0 and it seems to be working fine. Thanks for the help.