Have you tried to restart Firefox?

If so, try restarting on Diagnose Firefox issues using Troubleshoot Mode. It doesn't sound normal at all.

Let us know if it works.

Do you have an extension like TACO (Abine) or TrackerBlock that maintains a set of OPT-OUT cookies?

• Targeted Advertising Cookie Opt-Out (TACO): https://addons.mozilla.org/firefox/addon/targeted-advertising-cookie-op/
• TrackerBlock: https://addons.mozilla.org/firefox/addon/trackerblock/
• Beef Taco (Targeted Advertising Cookie Opt-Out): https://addons.mozilla.org/firefox/addon/beef-taco-targeted-advertising/

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.org/kb/Safe+Mode

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Went right to the Trackerblock extension and thought everything was checked correctly. Your suggestion of checking the Opt-Out was right on. Once I un-checked the box for Opt-Out, I was able to delete cookies as before.

Thanks !!

Started FireFox several times without improving results to delete cookies. I also tried FireFox in Safe Mode, and that did help, but where to find the problem (my time is limited due to work). I'm sure I changed something in the past 1-1/2 weeks that changed the cookie setting, but what. I'll keep searching.

Thanks

If clearing the cookies doesn't help then it is possible that the file cookies.sqlite that stores the cookies is corrupted.

Rename (or delete) cookies.sqlite (cookies.sqlite.old) and delete other present cookie files like cookies.sqlite-journal in the Firefox Profile Folder in case the file cookies.sqlite got corrupted.

• http://kb.mozillazine.org/Cookies