A 'Not Responding' message means the computer CPU is being overworked. The cause could be anything (computer doing other work, script problems, add-ons not compatible with each other . . . . .).

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/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-hangs-or-not-responding

Thanks, FredMcD, I tried the links you suggested, but no change. I just started using FireFox, as my previous browser/homepage was att.net which just had a major renovation that slowed it to a crawl. I still have att.net on my computer and suspect that it may be interfering with FireFox. Is that possible?

I checked out http://start.att.net/ and it looks okay to me.

jimmcconnell said

I still have att.net on my computer and suspect that it may be interfering with FireFox. Is that possible?

Are you talking about a program or a bookmark?

If a program, disable it. A bookmark just sits in the manager until used.

Thank you, Fred!

Glad to help. Safe Surfing.

I use FF 53.0.3 and was getting "Not Responding" freezes every 20-30 seconds for the last 3 updates. After looking over everyone's suggestions, I went into the Adds-on section and disabled almost all of the add-ons that have a note saying "incompatible with microprocess." Since then, ZERO "Not Responding" messages and a seemingly faster response as I surf.

David

cloverdavid said

I use FF 53.0.3 and was getting "Not Responding" freezes every 20-30 seconds for the last 3 updates. After looking over everyone's suggestions, I went into the Adds-on section and disabled almost all of the add-ons that have a note saying "incompatible with microprocess." Since then, ZERO "Not Responding" messages and a seemingly faster response as I surf. David

When you say   "microprocess"   -   you probably mean   'Multiprocess' (e10s), right   ?

Yes, that's what I meant. I didn't pay much attention to the word, as I don't have a clue about what it is or why I should know it, or what it means that an add-on is not compatible with multiprocess. What does it mean for me? Who is fixing the add-ons? David

cloverdavid said

Yes, that's what I meant. I didn't pay much attention to the word, as I don't have a clue about what it is or why I should know it, or what it means that an add-on is not compatible with multiprocess. What does it mean for me? Who is fixing the add-ons? David

Sounds like you shouldn't have disabled add-ons,   but the Multiprocess feature instead. Question is :   are you using Multiprocess (e10s)  ? You can check whether you have this feature turned on as follows : • '3-bar' menu button => ' ? ' button => Troubleshooting Information • type 'about:support ' (without the commas) in the address bar and press Enter/Return In the first table on the page, check the row for 'Multiprocess Windows' and see whether the number on the left side of the fraction is greater than zero. If so, you are using e10s - otherwise it should read : 0/1 (Disabled).

If you are using e10s: You could turn it off as follows : Type in the address bar about:config (promise to be careful, if asked) Type and search for the preferences : browser.tabs.remote.autostart and set it's value to false browser.tabs.remote.autostart.2 and set it's value to false

Note: the exact name of the preference may vary, but it will start with browser.tabs.remote.autostart

(It would have been better if you had started a new question,
though   -   please, do so, should you have anymore questions
pertaining to this issue, okay   ?)

cloverdavid said

or what it means that an add-on is not compatible with multiprocess.

Multi-process is a way that Firefox tries to divide the workload. In this way, if one part of FF locks up, the other would keep running.

If you see that an add-on is not compatible, that only means that multi-process is disabled.

cloverdavid said

I went into the Adds-on section and disabled almost all of the add-ons

One of the add-ons you disabled may be the problem. Re-enable those add-ons One At A Time (restarting Firefox) untill the problem returns.

Then disable that, and restore the others. Let us know who the trouble maker is.