Hi, 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 60.0.2 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.

What version were you using before? In Firefox 57+, the "Tab Mix Plus" extension no longer works, so link behavior now needs to be handled by other settings/add-ons.

Links and Tabs

The setting you mentioned is not for ALL links, only some links. It is for links the site coded to open in a new window. Firefox opens them in a new tab instead of a new window.

When a site does not specially code the link, it normally opens in the same tab. You can divert it to a new tab yourself by holding down the Ctrl key when clicking, or middle-clicking with the mouse scroll wheel.

There is an add-on to take care of that automatically ("Open Link with New Tab"):

https://addons.mozilla.org/firefox/addon/open-link-with-new-tab/

After installing, you need to use the Add-ons page to set your preferred behavior. Either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons
• type or paste about:addons in the address bar and press Enter/Return

In the left column of the Add-ons page, click Extensions. Then find the extension on the right side and click its Options button or More link. That should take you to the panel where you can adjust its settings.

Scripted Popups

If scripted popups still launch in a new window, you can force them into a new tab instead using this setting:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful or accepting the risk.

(2) In the search box above the list, type or paste link.o and pause while the list is filtered

(3) Double-click browser.link.open_newwindow.restriction and edit the value to 0 (that's a zero) to divert both regular AND scripted windows with features to a new tab instead (assuming you have Firefox set to divert windows to a new tab instead)

locking this thread - please continue here - https://support.mozilla.org/en-US/questions/1221126