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The new upgrade to Firefox 4.0 has rendered the browser useless. Error message is XUL Runner Platform Version 2.0.1 not compatible with minVersion>=2.0 maxVersion<=2.0. How do I get any version of Firefox to load again?

  • 6 cavab
  • 95 have this problem
  • 12 views
  • Last reply by Rory

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XUL Runner Platform Version 2.0.1 not compatible with minVersion>=2.0 maxVersion<=2.0

XUL Runner Platform Version 2.0.1 not compatible with minVersion>=2.0 maxVersion<=2.0

All Replies (6)

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Hey everyone, I was able to fix my firefox. Check out the XUL Runner error section here: http://kb.mozillazine.org/Browser_will_not_start_up

Basically I renamed the Firefox folder in programfiles to Mozilla Firefox.old (I didn't want to delete it just in case). Then reinstalled firefox.

All my bookmarks and passwords are still there.

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Ted, I had this problem after the automatic upgrade from 4.0 to 4.0.1. (Re)installing FF portable 4.0.1 from PortableApps.com resolved the issue, and all of my settings were left intact (I did not uninstall before installing).

-RM PS: I use the Portable Apps platform to manage my apps, don't know if the results would be different if the platform is not used.

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I simply uninstalled Firefox and reinstalled 3.6 and everything works again. I did not lose any information, but I had to uninstall from the Control Panel and rename my Program File. Firefox will still not load if Zone Alarm is running (too unstable). I have to exit Zone Alarm, open Firefox and then reopen Zone Alarm. Does anyone ever test these updates before they release them? The attitude seems to be that everyone is out of step but the Firefox "engineers".

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Where did you go to get a previous version?

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Do a clean (re-)install:

  • Download a fresh Firefox copy and save the file to the desktop.
  • Firefox 4.0.x: http://www.mozilla.com/en-US/firefox/all.html
  • Firefox 3.6.x: http://www.mozilla.com/en-US/firefox/all-older.html
  • Uninstall your current Firefox version and remove the Firefox program folder before installing that copy of the Firefox installer.
  • Do not remove personal data if you uninstall the current version.
  • 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 (not in the Firefox program 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.

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My solution to this was to turn off Browser Security in ZoneAlarm Extreme Security. When Firefox loaded, I turned Browser Security back on. This seems to cure other Firefox failures as well.

Firefox and ZoneAlarm need to talk!