Unfortunately, many sites do depend on third-party cookies, so disabling them everywhere by default isn't an option. However, starting in Firefox 65 (which will be released in January), Firefox will block third-party cookies from tracking resources by default, which should signifcantly reduce the impact of this issue while minimizing the number of sites that don't work correctly. You can read more about this here: https://blog.mozilla.org/futurereleases/2018/08/30/changing-our-approach-to-anti-tracking/.

yessongs1 said

The newest version, 63.0, makes it a bit more of a pain to manage TPC.

In what way? I guess the fact that you now have two places to manage third party cookie settings is a little confusing:

(1) Under Content Blocking

• Allow third party cookies (default -- box is not checked)
• Block third party cookies from tracking servers (check box and use first button)
• Block all third party cookies (check box and use second button)

(2) Under Cookies and Site Data

• Allow third party cookies (default -- Accept cookies and site data is selected)
• Block third party cookies from tracking servers (select "Block cookies and site data" and use first option in the drop-down)
• Block third party cookies until you have directly visited the site at least once (select "Block cookies and site data" and use second option in the drop-down)
• Block all third party cookies (select "Block cookies and site data" and use third option in the drop-down)

Those work out the same except that "From Visited" (Safari style) is only under the second section.

Note that Sync relies on local storage and cookie and won't work when all cookies would be blocked by default. Most or all websites should work with the default settings and a lot of website rely on cookies to work properly.

See also:

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