Yep, I haven't been able to host co-op since April 23rd. It isn't the save. I completely wiped D:OS and Steam from my pc. All the folders, regedit entries, etc. Didn't matter.
I made the mistake of alt-f4ing the game when it got stuck at "releasing data" and haven't been able to host since. Then, it happened again but with my friend hosting (my game crashed upon loading a new area, he got stuck at loading screen). I told him to wait and see if it would load eventually then I'd rejoin the game but it never did. So then I was like "Well.. let me try rejoining before you restart". After I rejoined him it loaded the next area normally (about 5 seconds after pressing the join button, after a few minutes of waiting to see if it'd load). I assume if he would have closed D:OS at that time he wouldn't be able to host anymore, but we didn't want to risk not being able to play co-op with each other at all.
The only tip I can give people is if you are the host of a co-op game, do not restart your game if it looks like it has frozen on the loading screen. Instead, wait for your co-op partner to restart his game and rejoin you. Then it should load normally. Of course this bug could have more causes, to which this advice would be useless (Sadly, in our case it's too late, we're bugged until Larian can figure it out, though I may try a reformat if it isn't fixed by the time the full game launches). All my other random CTDs didn't seem to cause it though as I was still able to restart and re-host co-op just fine on several normal CTDs, only the alt-f4 at the loading screen seemed to put the nail in the co-op coffin. /shrug
Last edited by demise; 05/05/14 12:51 PM.