Hi spuroneman, I do not think that there is a compatibility mode in Firefox, but I am still learning, so I could be wrong. It is possible to turn off these add ons in the add ons menu.

If they are not there you can try a new profile or a Firefox reset, it will remove addons. Reset is done by going to the url about:support and clicking the Reset Firefox button.

Hello Very good to hear from you,much appreciated. The compatibility screen comes on when FF updates to latest platform ,checking that your add-ons are compatible with new issue.

after at the last but one update,the compatibilty box comes up everytime I click on FF,and also the theme & font add on and the side bar for ebay. I have tried most things but they refuse to stop.

any further help appreciated

best wishes Steve

Hi Steve, (rolling up the sleeves :-)) To make sure you are not clicking on the installer, do you have more than one icon of Firefox in your list of programs?

Do you have the latest version of the sidebar 3.15? Does this happen when it is disabled? Is the add on updated? You can check from the about:addons page and click on the update button on the top right.

I created a new profile in version 33 and added the ebay side bar and the theme and font changer. I added a change to the theme and restarted it in safe mode. The weird thing was that the background color stayed the custom color.

"Did you make sure that all check-boxes on the Compatibility tab of the Firefox desktop shortcut and the Firefox.exe file in the Firefox program folder are unchecked ?"

You can check for problems with preferences.

Delete possible user.js and numbered prefs-##.js files and rename (or delete) 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 the current Firefox release.

• http://kb.mozillazine.org/Preferences_not_saved
• http://kb.mozillazine.org/Resetting_preferences

It is possible that there is a problem with the file(s) that store the extensions registry.

Delete the extensions.* files (e.g. extensions.json, extensions.sqlite, extensions.ini) and compatibility.ini in the Firefox profile folder to reset the extensions registry.

• https://support.mozilla.org/kb/Profiles

New files will be created when required.

See "Corrupt extension files":

• http://kb.mozillazine.org/Unable_to_install_themes_or_extensions
• https://support.mozilla.org/kb/Unable+to+install+add-ons

If you see disabled or not compatible extensions in "Firefox/Tools > Add-ons > Extensions" then click the Tools button at the left end of the Search bar to check if there is a compatibility update available.

If this hasn't helped then also delete possible addons.json and addons.sqlite files.