-> Clear Cookies & Cache

• https://support.mozilla.com/en-US/kb/Template:clearCookiesCache

-> Clear the Network Cache

Check and tell if its working.

Thank you, Mha007. I had tried that and had set my options for cache and network to clear when I exit the browser. However, the cookies reappear when I open the browser. I think I will uninstall and try reinstalling. I appreciate your time and effort.

-> Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

Now repeat the the steps mentioned in the the articles provided in my previous reply.

Check and tell if its working.

I have followed the steps in your last reply and the cookies remain after I close Firefox and renter. They leave temporarily but return whenever I open the browser.

Did you try opening Firefox in Safe Mode and then Clearing your Cookies & Cache while using Firefox Safe Mode ??

I tried opening in no-scripts and the cookies remained. I really think I somehow received these cookies during the download. Nothing I have tried deletes them permanently.

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.com/kb/Safe+Mode

Hello Cor-el. Taco & Abine did not resolve the issue nor did ABP but I had not tried Tracker Blocker or Beef Taco. I did try running in NoScripts but the cookies remained. I honestly do not understand how I obtained these cookies unless I downloaded from a site other than Mozilla Firefox. The cookies seemed to be in the download and I saw in Yahoo Answers, others that had encountered this issue. The cookies were present before I could sign into a site. One user said she went to the Mozilla folder in her computer and deleted them there but I was unable to find them. What I did do was to go to the Mozilla Firefox site, specifically, and downloaded the browser after uninstalling the bad load. In this new load, every thing is fine! I only wish I knew the source of the problem!

I sincerely appreciate the help; the time and effort in the resolution of this issue. Many thanks.

Can you remove those cookies in Save mode or with all extensions disabled?

If that works then are they still gone if you restart another time in Safe mode?

• https://support.mozilla.com/kb/Safe+Mode
• Help > Restart with Add-ons Disabled

I could delete them but they "all" returned each time I closed and reopened the browser. The opt out cookies in Tracker Block were among those in the browser plus others like "yieldmanager" and "atdmt" and nothing would remove them permanently including the block list in Firefox options. I made a filter in ABP as well as on the ff block options but they returned whether in normal mode or no scripts. I made a mistake before; Taco, Abine, Beef Taco and TrackerBlock were installed at the time along with ABP and Ghostery.

You can't remove opt-out cookies that are added by an extension as long as that extension is enabled or installed. If you choose to install such an extension then you have to accept the presence of 100 or more cookies added by the extension.

Thank you, Cor-el. I had only just begun to figure that out; uninstalled and reinstalled without some of the extensions. The situation is taken care of and I am satisfied with the outcome. You are so helpful and kind! It was your suggestions that forced me to take a better look at the situation and you who resolved the issue. I appreciate your tenacity in locating a resolution!!! Thanks again, Cor-el.

You're welcome

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

-> Basic Troubleshooting - Make a New Profile

IF that New Profile works then you can recover your Bookmarks and Passwords from the Old Profile.

-> Recover important data from an old profile

Check and tell if its working.