Unsupported browser - FF 33.02

Question

Hello,
Just updated to FF33.02 and I'm getting messages now on various sites that the browser is not supported.
Gmail: This version of Firefox is no longer supported. Please upgrade to a supported browser.
Yahoo Mail: You’re seeing Basic Mail because you’re using an unsupported Internet browser. Upgrade your browser or get the mobile app for the full Yahoo experience.
I have restarted the browser with add-ons disabled as well, but the messages persist. I cannot understand why suddenly I'm getting these messages when I was not getting them while still using 27.0.1.
Are these messages an attempt by the websites to force users to use Chrome or another browser which is not FF?
Cheers!
Sarah

Answer 1

You can check for problems caused by a possible corrupted user agent.
See:
*https://support.mozilla.org/kb/Finding+your+Firefox+version
*https://support.mozilla.org/kb/websites-say-firefox-outdated-or-incompatible
You can check how websites see you on the browserspy.dk website.
*http://browserspy.dk/useragent.php
Such an issue can also be caused by security software.
Boot the computer in Windows Safe mode with network support (press F8 on the boot screen) as a test to see if that helps.
*http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
Do a malware check with several malware scanning programs on the Windows computer.
Please scan with all programs because each program detects different malware.
All these programs have free versions.
Make sure that you update each program to get the latest version of their databases before doing a scan.
*Malwarebytes' Anti-Malware:<br>http://www.malwarebytes.org/mbam.php
*AdwCleaner:<br>http://www.bleepingcomputer.com/download/adwcleaner/<br>http://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml
*SuperAntispyware:<br>http://www.superantispyware.com/
*Microsoft Safety Scanner:<br>http://www.microsoft.com/security/scanner/en-us/default.aspx
*Windows Defender:<br>http://windows.microsoft.com/en-us/windows/using-defender
*Spybot Search & Destroy:<br>http://www.safer-networking.org/en/index.html
*Kasperky Free Security Scan:<br>http://www.kaspersky.com/security-scan
You can also do a check for a rootkit infection with TDSSKiller.
*Anti-rootkit utility TDSSKiller:<br>http://support.kaspersky.com/5350?el=88446
See also:
*"Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked
*https://support.mozilla.org/kb/troubleshoot-firefox-issues-caused-malware