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?

Try to disable multi-process tabs in Firefox. You can disable multi-process tabs in Firefox by setting the related prefs to false on the about:config page.

browser.tabs.remote.autostart = false browser.tabs.remote.autostart.2 = false

http://www.ghacks.net/2016/07/22/multi-process-firefox/

Type about:config<enter> in the address bar. If a warning screen comes up, press the Be Careful button. At the top of the screen is a search bar.

autostart.2 was true and I toggled it to false, closed and reopened FF and it quickly loaded all ten tabs (my home pages), using only 1000 MB of memory (per task manager). I guess that's it! Thanks a lot, man. Just checked: all ten tabs and the browser itself are happy and stable.

Glad to help. Safe Surfing.

New wrinkle, opening a Sudoku puzzle at the local daily paper's website, heavy with advertising, the puzzle itself won't display, and FF is off to the races. My normal ten tabs, home pages, settled, after the adjustment you advised, to using less than a 1000 MB memory. Trying to add this page, or going to it from my Google tab/homepage, has memory usage up to 2000 and still no puzzle. This is the second try this morning. First time, memory usage got up to 3000 and FF started yellow-flagging, not responding. It ought to just give up and say it can't open the puzzle. First time around, it was getting the numbers to display and the buttons but not the grid, after refreshing the tab several times, but then it waved the yellow flag. Now it's up to 2400 on the second try. 2600.

Third trial, and I'm not sure your measure changed anything. Left alone, FF starts piling up the memory MBs, and then my navigating away from my ten home-page/tabs, I don't know if that accelerated the pile-up/lock-up. But it got here, when memory usage gets much beyond 3000 mb. But 1000 or so is all it needs to initially open the 10 pages.. I should add to my previous reply that I'm not sure FF was ever able to open the sudoku page: maybe it's a too-messy webpage security-wise. http://www.pressherald.com/sudoku/ But it now looks like my original complaint stands: left alone, my ten-tab homepage train-wrecks after that incremental memory usage build-up.. On my third trial this morning I didn't go to that puzzle page.

I think there is a problem with the puzzle page. My browser started locking up until I stopped the scripts.

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Go to that message, and use the Undo link to its right.

Deleted, added a line to previous post.

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

By task manager, starting FF in Safe got all ten tabs of my home-page loaded in about 600 MB of memory versus about 1200 in normal start-up, but in both cases, left alone, FF began to gobble up memory. While I've been typing this, FF in Safe has gone from 800 to 1233 +/-. I'll try the Appearance to Default step now. I correct my number on normal memory usage at start-up to around 900. I can't remember what the Appearance setting was when I first looked at it: on Safe, all three options were disabled, and when I looked again after normal start-up, I changed something, arrived at Default, but can't swear it wasn't on Default already. In any case, now FF has been running for the time it took to type this, on normal start-up and with Appearance set to Default, and memory usage is at 1750-some. Reread to check, memory now up to 2130-some. Another afterthought: when I close FF (exit on File menu), it takes towards half a minute for memory usage to get back down, so I noticed FF running on "Background", which closes out after that half-minute delay; when I exit, FF immediately disappears from "Apps", this is all under the Processes tab of Task Manager, "Apps" being the first category listed, and, after "Background", comes "Windows". Which at least tells you how much I know about computers.

When multi-process windows in Firefox is enabled then Firefox will use more memory and may be less responsive.

You can try this to see if it has effect:

• set dom.ipc.processCount to 1 if it is currently set to a higher value (4)
• disable multi-process windows in Firefox

You can disable multi-process windows in Firefox by setting these prefs to false on the about:config page.

• browser.tabs.remote.autostart = false
• browser.tabs.remote.autostart.2 = false

You can open the about:config page: via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

• http://kb.mozillazine.org/about:config

• http://www.ghacks.net/2016/07/22/multi-process-firefox/

Fred McD (above) already had me do the browser.tabs.remote.autostart = false steps (autostart2 had been set to true), and I just checked the dom.ipc.process.count and it's already set = 1.