Please look for on the Start Menu, buried under Admin I think...or search for Task Manager (Taskmgr.exe) shut down any running processes of Firefox.

Or boot to Safe Mode : https://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/boot_failsafe.mspx?mfr=true

And do what ever you want to do.

Suggest join rest of XP users on 52.5.3 ESR. It will continue to get security updates until May 2018, and you can download and install it from this page: *https://www.mozilla.org/en-US/firefox/organizations/all/ Note : Legacy Extensions will be deleted or removed in any version update after May 2018.

You should make a backup of your Profile before going back and just because:

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

Please let us know if this solved your issue or if need further assistance.

Thank you but not possible to use. I mentioned MAC, High Sierra it's operating system version, and Finder - the MAC version of Windows Explorer.

As I read it you seem to think I am on Windows XP. I do have that on my old computer but the Firefox problem is on my new MAC

Thanks again

Yes do as the information here says you sent the issue on a XP System Details Windows XP Firefox 38.9

mouse45 said

It leaves an icon on the screen which will not delete. At the Finder window trying to drag it to the trash it says it cannot be deleted. I am new to Firefox on Mac. If anyone can help please make it simple to follow. Thanks

https://support.mozilla.org/en-US/kb/how-download-and-install-firefox-mac

mouse45 said

As I read it you seem to think I am on Windows XP. I do have that on my old computer but the Firefox problem is on my new MAC

See https://support.mozilla.org/en-US/kb/how-reset-default-user-agent-firefox

This is why people responding to threads needs to pay attention to the OS details like the "high sierra" "Mac" and "finder" mentioned in the OP and not mainly on what it says under system details. Not uncommon for people to ask a question while using a different OS or system or to have a useragent that is changed in some way.