Please consider turning on send info to Mozilla before posting a question. This helps us help you. As I have no info from your system that would help see things that cause issues.

Try : Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

https://support.mozilla.org/kb/Firefox+is+already+running+but+is+not+responding

https://support.mozilla.org/en-US/kb/firefox-slow-how-make-it-faster

https://support.mozilla.org/en-US/kb/firefox-uses-too-many-cpu-resources-how-fix

https://support.mozilla.org/en-US/kb/firefox-uses-too-much-memory-ram

https://support.mozilla.org/en-US/kb/firefox-hangs-or-not-responding

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

NO!!! My problem is not fixed. Both Safemode and regular mode have the same problem. The program does not shutdown properly either. I Have to use Task Manager to close. I am using < 22% of the CPU and have plenty of memory. This version seems to use more memory. I am typing this using Google Chrome as Firefox is too dysfuctional to type anything. I wish I had my old version back. It worked OK . The send options in Fire fox are checked.

Why did you guys do an upgrade that makes us have to uninstall, reinstall, delete directories, go into safe mode, on and on. This is a disaster. Roll it back.

Whoops, just found a solution to my problem: Chrome.

I have this problem too. Since the upgrade my cheap smartphone is now faster than my desktop computer.