Hi, could you try this please try this : uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files , C:\Program Files(x86) & C:\ProgramData Then restart system. Then run Windows Disk Cleanup. (Note: This should be Pinned and run Weekly, If never done below expect 10's of gig's) Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. But you should make a back up before you do :

• 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

Reinstall with Current Release Firefox 59.0 with a Full Version Installer

• https://www.mozilla.org/firefox/all/

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

In case the above doesn't do the trick :

Are you using Tracking Protection  ?

In that case, would you please turn it off on that page and see if that will make a difference  ?

See : https://support.mozilla.org/en-US/kb/tracking-protection

Pkshadow : I tried uninstalling as you suggested, but it didn't fix the issue.

Happy112: Tracking protection is off.

Does anyone else know what could be causing this? Thank You.

It could be the work of one of your extensions (providing you have any), so let's try Firefox in Safe Mode :

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

If Firefox is running : 3-bar menu => ' ? ' (at the bottom of the dropdown) => 'Restart with Add-ons disabled'. Then OK the restart. A small dialog should appear. Click 'Start in Safe Mode' ( not 'Refresh' !)

See : https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode

Does that make the 'Like' icons reappear  ?

You can check the Web Console (Tools -> Web Developer) for messages about blocked content and about the presence of mixed or unsafe content.

• https://developer.mozilla.org/en/Tools/Web_Console

You can check the Network Monitor to see if content is blocked or otherwise fails to load.

• https://developer.mozilla.org/en/Tools/Network_Monitor

If necessary use "Ctrl+F5" or "Ctrl+Shift+R" (Mac: Command+Shift+R) to reload the page and bypass the cache to generate a fresh log.

Thanks for replying.

Happy112: Safe mode with no extensions - no change.

cor-el: Network Monitor shows all green 200's under status when I hover over like and the icons fail to load.

Web Developer: You didn't provide enough information for me to determine if there are "messages about blocked content and about the presence of mixed or unsafe content"

UPDATE Facebook fixed itself spontaneously. Thank you for your replies and time.