Do you have security software that might be messing with the extensions files (extensions.ini, extensions.json) in the profile folder?

Create a new profile as a test to check if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Thanks, but as stated in my original post, I tried creating a new profile. Problem still occurs with the new profile without copying anything from the old profile.

What security software do you have?

There is also software like Advanced SystemCare with its Surfing Protection feature that can protect files in the Firefox profile folder against changes. If you have such software then check the settings or uninstall this software.

Boot the computer in Windows Safe mode with network support (press F8 on the boot screen) to see if that has effect.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• http://www.7tutorials.com/4-ways-boot-safe-mode-windows-10

Thanks for the tip on security software with browsing protection feature. As it turned out, I didn't have any anti virus or malware software installed. I did a quick run of malwarebytes anti malware and it removed a few threats. I then installed avast anti virus and turned off browsing and email protection.

After several firefox restarts, including several computer reboots, no problem with the addons uninstalling.