The file "permissions.sqlite" stores 'allow' and 'block' exceptions for cookies, images, pop-up windows, and extensions (software) installation.

Rename the file "permissions.sqlite" to permissions.sqlite.sav in the Firefox Profile Folder in case the file is corrupted.

• Help > Troubleshooting Information > Profile Directory: Open Containing Folder

This will remove all exceptions (cookies, images, pop-ups, software).
If renaming didn't help then you can undo and rename the file permissions.sqlite.sav to permissions.sqlite to get back the old exceptions.

I'm sorry I don't understand your reply. If renaming this file will remove all exceptions, how does this help me? I want to retain the exceptions not remove them, which is what is happening now each I quit). Also, if I undo the renaming of the file, then I will be back to where I was before, which was that the exceptions are being deleted anyway each time I quit FF.

Also, where is this file located? Your path doesn't make sense to me. I can't find any folder called Profile directory or Help.

See:

• https://support.mozilla.com/kb/Using+the+Troubleshooting+Information+page

If there is a problem with the file and the exceptions aren't saved then deleting the file permissions.sqlite will cause Firefox create a new copy that hopefully works better.

I have renamed the file as you suggested above. The list of block and allow sites in the Privacy area of preferences are still being deleted.

I had a similar problem, but mine was the exception list for blocked images. This exception list is also stored in the profile permissions.sqlite file. I finally figured out this was being cleared because I had set my privacy settings to clear site settings on shutdown.

To change this, go to Tools->Options-> Privacy Tab. If your problem is the same as mine, on this tab you will have the "Clear history when Firefox closes" box checked. Then click the "Settings" button, and in the pop-up under the data section, un-check the "Site Preferences" box.