Hello! We are excited to announce Steam Families is now available for all users. Steam Families is a collection of new and existing family-related features. It replaces both Steam Family Sharing and Steam Family View, giving you a single location to manage which games your family can access and when they can play. Create a Steam Family To get started, you can create a Steam Family and then invite up to 5 family members.
How does this effect that?
My guess is this, which is way at the bottom of the support FAQ page (which can be found at the bottom of the posted FAQ section):
“I cannot join a Steam Family”
If you cannot join a Steam Family, it is likely for one of three reasons:
I cannot invite my gf to the Families, while we could do Library share before just fine.
Why not?
Replied in other posts, it likely is because you have to be in the same country/steam store region or something…
A lot of work but: have her VPN into your residential network and send her traffic through your ISP for a while.
5head tactics haha.
Just sign in with her account on your pc, invite her and then you can sign out. I had the same problem.