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XULRunner error: Platform version '64.0' is not compatible with minVersion>=63.0.3 maxVersion<=63.0.3

  • 6 replies
  • 11 have this problem
  • 24044 views
  • Last reply by cor-el

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When I started Firefox this morning, I got the error message in the subject line this morning. The only button is "OK", which banishes the error message. The browser doesn't show up.

This evening, I checked for Windows updates, and the only ones pending were security definition updates and Silverlight (which I don't knowingly use).

A google search of the following doesn't yield anything helpful:

XULRunner error "Platform version '64.0' is not compatible with" "minVersion >= 63.0.3" "maxVersion <= 63.0.3"

If anyone can suggest anything, thanks....I am running Windows 7

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Chosen solution

An error message about XPCOM missing or about platform version usually happens because of a failed Firefox update that left you with a mixture of old and updated files in the Firefox program folder. This can happen in case security software was keeping a handle of some of the files in the Firefox program folder preventing Firefox from replacing all the files. You need to do a clean reinstall and remove the Firefox program folder to ensure that all files are replaced. You may have to disable security software temporarily in case the problem persists.

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All Replies (6)

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I also tried running firefox in safe mode, but I get the same pop up error message.

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I got the same popup error when I tried to start Firefox from an admin account, so it's not related to a user profile.

Eventually, I deleted Firefox, downloaded the current version, reinstalled, and experienced no further problems.

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Chosen Solution

An error message about XPCOM missing or about platform version usually happens because of a failed Firefox update that left you with a mixture of old and updated files in the Firefox program folder. This can happen in case security software was keeping a handle of some of the files in the Firefox program folder preventing Firefox from replacing all the files. You need to do a clean reinstall and remove the Firefox program folder to ensure that all files are replaced. You may have to disable security software temporarily in case the problem persists.

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FoxyFirey That was very good work. Well done. Please flag your last post as Solved Problem so others will know.

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Same problem. I eventually got a message saying Firefox is not the default browser, do you want it to be? Setting FF as default solved the problem for me.

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This specific error message can't be a real problem with the default browser. This is always a problem with files in the Firefox program folder that haven't been updated properly and is likely caused by security software that is interfering with updating files. It is possible that this issues got corrected automatically after a few Windows restarts.