Please Refresh but do this 1st:

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

then

• https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings

TEST....... If no issues then Extensions which need to be added back in 1 at a time and tested ..... Or it is your Profile : Make a new one and test ...:

• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

If is your Profile :

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile
• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Note: Any customization will revert back to default, you will also need to reinstall Extensions.

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

Update: There is a fix for uBlock Origin filters to address this problem if yours is caused by that extension. See: https://www.reddit.com/r/uBlockOrigin/comments/7mxddl/facebook_newsfeed_going_crazy_when_ublock_on/drxioqo/

I wonder if you have tried "the usual":

If a site is generally known to work in Firefox, these are general suggestions to try when it stops working correctly:

Cache and Cookies: When you have a problem with one particular site, a good "first thing to try" is clearing your Firefox cache and deleting your saved cookies for the site.

(1) Clear Firefox's Cache

See: How to clear the Firefox cache

If you have a large hard drive, this might take a few minutes. If you do not see the number going down on the page, you can reload it using Ctrl+r to check progress.

(2) Remove the site's cookies (save any pending work first). While viewing a page on the site, try either:

• right-click (on Mac Ctrl+click) a blank area of the page and choose View Page Info > Security > "View Cookies"
• (menu bar) Tools > Page Info > Security > "View Cookies"
• click the padlock or "i" icon in the address bar, then the ">" button, then More Information, and finally the "View Cookies" button

In the dialog that opens, the current site should be pre-filled in the search box at the top of the dialog so you can remove that site's cookies individually.

Then try reloading the page. Does that help?

Testing in Firefox's Safe Mode: In Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is not running: Hold down the Shift key when starting Firefox.

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" button > Restart with Add-ons Disabled
• Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement?

Greetings,

I was having the same error, so I tested all the above and Safe Mode seemed to help me.

So i went to my Add-Ons and the one that was causing the problem was Ublock Origin (ad-blocker)

Try disabling it and see if it helps.

I concur that the culprit is Ublock origin, HOWEVER...

It wasn't Ublock origin that got updated and broke Facebook. If Firefox gets updated and a major site breaks (with one of the most popular and featured addon) then it is at least a little bit Mozilla's problem.

Also, other sites broke too - at least for me. For example JSFiddle cannot be resized since the update, whereas it works still just fine in Chrome.

Edit: To be clear, JSFiddle broke because of Ublock origin as well. But they did right after the FF update.

Edit2: By now, JSFiddle seems to work without being on Ublock origin's whitelist. These breaks might have been coincidental.

According to the following thread, there is a filter update available to fix the FB problem, but you may have to force update multiple times. I don't know what that means...

https://www.reddit.com/r/uBlockOrigin/comments/7mxddl/facebook_newsfeed_going_crazy_when_ublock_on/drxioqo/

Indeed force-updating Ublock's filters fixed my problem.

Thanks for your help!

Thank you!