Show us what error you are getting. What security software are you using? Have you tried Firefox in Safe Mode? https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#w_how-to-start-firefox-in-4troubleshoot-modesf5safe-modesf

Under 'More System Details' I found {"name": "Web Threat Shield", "type": "extension", "version": "1.12.20265.1", "isActive": true, "id": "webrootsecure@webroot.com"}

Could this be relevant? A couple of other users identified Webroot (security software) as blocking 64-bit Firefox 97 -- released today -- from running properly:

• https://support.mozilla.org/questions/1367248
• https://support.mozilla.org/questions/1367301

If you are still running an earlier release of Firefox, this would not be your issue.

Thanks for the info. I suspect that Webroot and the Firefox update must be the issue. I guess I'll just switch to Microsoft Edge as my browser. Seems like the easy solution at this point.

https://www.mozilla.org/firefox/97.0.1/releasenotes/

Fixed Works around problems with WebRoot SecureAnywhere antivirus rendering Firefox unusable in some situations

James, Thanks for the resolution. I'm not very I.T. savvy but you and the team made it easy. Glad to be back up and using Firefox / Mozilla! Mike