Went into Firefox and got the error message: Platform version 131.03 is not compatible with min version>=131.02 & max version>=131.02

Install Firefox again with a full installer. You shouldn't lose any data.

The full offline setup for Windows can be downloaded from https://www.mozilla.org/firefox/all/#product-desktop-release as downloading Firefox for Windows from mozilla.org may serve you the small online stub installer.

An error message like XPCOM missing or about platform version or entry points not found can happen because of a failed Firefox update that left you with a mixture of old and updated files in the Firefox installation 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 reinstall Firefox and possibly 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.

Not quite sure what to do, I downloaded Firefox again, and was going to uninstall and reinstall. But as soon as the download finished, it loaded. So now I have the new Firefox without all of my saved bookmarks and passwords. I thought I'd read someplace that that wouldn't happen, and all of my password and bookmark history would transfer to the new Firefox.

Enter about:profiles in the address bar and find your old profile.

Thanks for the reply. If I understand this correctly, I should download Firefox (Windows 64 bit) from the link you sent. Then just run the .exe file? Do I have to uninstall the old Firefox first? Thanks

No, you don't have to uninstall. Just run the exe or msi.

Thank you. Thank you. Thank you. Everything looks like it's back to where it was. Such a simple fix when you have the correct info. Thanks again.

Thanks! The download worked.

Well, I thought everything was back to where it was. Complete with all of the bookmarks, and all of my passwords. But not so. I must have 2 different Firefox programs loaded, and depending on where I open it, I either get the old one with all of the info. Or I get a different one with none of the older passwords or bookmarks files. I keep getting the message that Firefox is not my default browser, and do I want to make it the default. When clicking yes, it takes me to the newer one with all of the missing files. So how do I get only the older version to open? Do I uninstall everything Firefox then reinstall it from the download link provided in an the earlier message? More help please. Thanks

Apparently I have 2 profiles; one an older one with all of my bookmarks and passwords. And one that looks like a new one without all of the old info. The older one is labeled: default, and the new one is labeled: default- release. Can I simply delete the apparent new profile, and just use the older one labeled default? Thanks

Yes, you can delete the new profile.

Thanks for your reply. That's done. Now on to this. If I go into control panel, and click on programs, Firefox is listed twice. How do I figure out which program I'm using? I want to uninstall the extra one. Thanks again.

Thanks again to TyDaniu for your help in solving my issue. I figured out the correct Firefox program to delete, and everything seems to be sorted out......finally. So hopefully, now it's solved. (fingers crossed)