Fully updated verison of Firefox is returning messages that it is not a supported browser
On many websites, including for example (and reference to the screenshot shared) Firefox on my PC, which is running version 76.01 (64 Bit). I have received this message on numerous websites, but Xfinity is the one that I am remembering now. Visiting Google.com also displays a warning that I am using an outdated version of Chrome. It also happens on slack.com
These issues started happening suddenly and I cannot determine a cause.
Otherwise, Firefox has been flawless and I would like to keep it that way.
Thank you so much for your help!
Modified by andrew.toig
All Replies (3)
Ohh, it also happens on slack.com
Websites say that Firefox is outdated or incompatible even though it's the latest version https://support.mozilla.org/en-US/kb/websites-say-firefox-outdated-or-incompatible
This article is no longer maintained, so its content might be out of date.
Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.
- switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Themes
- do NOT click the "Refresh Firefox" button on the Safe Mode start window
- https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
- https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems
- - - -
You can check for problems with preferences.
You can delete possible user.js and numbered prefs#-##.js files and rename/remove the prefs.js file to reset all prefs to the default value including prefs set via user.js and prefs that are no longer supported in current Firefox releases.
You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.
- Help -> Troubleshooting Information -> Profile Folder/Directory:
Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder - https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data