Do you have an "Old Firefox Data" folder on the desktop as the result of a possible Refresh/Reset of Firefox?

When you Refresh/Reset Firefox then a new profile is created and some personal data (bookmarks, history, cookies, passwords, form data) is automatically imported. The current profile folder will be moved to an "Old Firefox Data" folder on the desktop. Installed extensions and other customizations (toolbars, prefs) that you have made are lost and need to be redone.

It is possible to recover data from the "Old Firefox Data" folder on the desktop, but be cautious not to copy corrupted files to avoid carrying over problems.

You would need the permissions.sqlite file to restore the exceptions.

• https://support.mozilla.org/kb/Recovering+important+data+from+an+old+profile

I don't think Firefox has created a new profile. There's no Old Firefox Data folder on the desktop, the default folder for preferences shows it was updated today but created in May 2014 when I set up this computer, and the extensions I've installed are still working. Also, Firefox only asks me about cookies when I go to new sites, not those I've already visited, which I take to mean it's reading the list of exceptions for accepting cookies. It just doesn't display the list when I go into options. I've accepted and blocked cookies from a few sites since I noticed the list was empty, as well as manually adding a couple of sites, but still nothing shows in the list.

I logged into my PC as a different user, changed the Firefox History setting from the default "Remember history" to "Use custom settings for history," and then visited some sites and accepted or blocked cookies. Then I checked the Exceptions list and all those sites had been added to the list. So clearly the problem is something specific to my user profile. Maybe it's corrupted, and the missing Exceptions list isn't the only thing wrong, just the only thing I've found so far.

Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac Options) key, and then starting Firefox. Is the problem still there?

I started Firefox in safe mode, and then the list of cookie exceptions displayed properly.

It could be the work of one of your add-ons. Type about:addons<enter> in the address bar to open your Add-ons Manager. Hot key; <Control>(Mac:<Command>)<Shift> A)

In the Add-ons Manager, on the left, select Extensions. Disable a few add-ons, then Restart Firefox.

Some added toolbar and anti-virus add-ons are known to cause Firefox issues. Disable All of them.

If the problem continues, disable some more (restarting FF). Continue until the problem is gone. After, you know what group is causing the issue. Re-enable the last group ONE AT A TIME (restarting FF) until the problem returns.

Once you think you found the problem, disable that and re-enable all the others, then restart again. Let us know who the suspect is detective.

The culprit appears to be CookieExFilter, which is logical, since it's associated with the cookie exceptions list, and also a real shame, since it made it so much easier to find a site in the list when I wanted to change or delete something.

Thanks for your help.

Glad to help. Safe Surfing. Contact their support for more help.

Hello,

I am glad to hear that your problem has been resolved. If you haven't already, please select the answer that solves the problem. This will help other users with similar problems find the solution more easily.

Thank you for contacting Mozilla Support.