Which security software (firewall, anti-virus) do you have?

Some security software has virtualization or sandbox features that may cause problems by protecting and restoring files in the Firefox profile folder.

Create a new profile as a test to check if your current profile is causing the problems.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer some files from an existing profile to the new profile, but be careful not to copy corrupted files.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

go to About:config and find plugins.hide_infobar_for_outdated_plugin then double-click on it, to toggle it to "TRUE".

Hi all, thanks for the replies but it didn't work. I uninstalled Firefox and reinstalled and then had further problems in that I couldn't install any add ons. I spent a couple of days at it and gave up. I am now using chrome and have uninstalled Firefox as I coundn't find out how to download an earlier version. Tks again. JBGarrod