if this indeed is a bug, I feel like its fault is on the game that you're trying to play and not on steam itself

It does it for multiple games. Clearly a Steam issue.

would be so kind as to give some examples of games where this happens?

Valheim & Deep Rock Galactic.

and what measurements have you taken in-order to try and solve this?

are you trying to join them just by clicking join game or are you waiting for an invite via steam then join from the pop up chat window?

getting an invite should be working and just clicking join game can break.

None? Steam shows me a black screen instead of connecting me. Clearly Steam is in the wrong here, or it would at least show me some sort of error message instead of a black screen.

you could always try reinstalling the games and steam

Looks like this bug has yet to be fixed. Valve, what are you doing?

Hey ! Me and a friend, who uses mods while I don't, encountered this same problem for the last few days.
Until now our joined games worked just fine, but now, when one of us tries to join the other, instead of having the illustrated loading screen, we got a black screen with only our cursor, being only able to be moved around, clicking left and right being useless.
We tried with the windowed games, it didn't work. We left the game and launched it back, to no avail.
We already had the same problem a few weeks back, and it solved itself without any update or manipulation after a few days of inactivity on it.

Somebody has an explanation ? A bit of help is always welcome.

I have a similar issue where when I send invites or try to join my whole pc will black screen. Any help?

This thread was quite old before the recent post, so we're locking it to prevent confusion.