Can you try to start Firefox in Safe Mode to see if Firefox works properly with no error? You can start Firefox in Safe Mode below:

• Windows/Mac: Go to Help > Restart with add-ons disabled
• Linux: Run firefox -safe-mode in the Terminal/Konsole

If Firefox opens up fine with no problems, it's probably one of your extensions that's causing the issue. You can re-enable your add-ons one by one until you find the one that causes the issue upon being re-enabled.

I typed this question very late last night, so the spelling was horrible! But, as I stated, I did disable everything, and although I didn't explicitly state it, I did this also via safe-mode. So no luck there, but thanks for trying. Jeremy

Create a new profile as a test to check if your current profile is causing the problems.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer some files from an existing profile to the new profile, but be careful not to copy corrupted files.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Thanks Moses, tried this - exactly the same problem! No Change..

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe Mode start window.

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

You can try to disable hardware acceleration in Firefox (you need to close and restart Firefox).

• Tools > Options > Advanced > General > Browsing: "Use hardware acceleration when available"

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Thanks, I've tried that too, with no luck.

Still the same problem!

Thanks all the same..

I found a work around!

I applied a new Theme add-on the tabs show text again!

Thanks for all those who tried to help.