I've tried it with 2 different partners, but when I host as central and they are thief, all they see is this and can't do anything: https://cdn.discordapp.com/attachments/957354714402533406/1075433846117507153/image.png . How to fix this?

Add me!

The red pipes puzzle at the end has got us stumped, we see some clues but nothing to help us solve it, I played both sides and still have no clue what there for.

This worked for me and my buddy. The problem apeard to be on my side. This fixed it and i dont know if all steps are needed. Go to your steam library,right click Heist United propperty's then general and turn of Steam Cloud for this. Then on your computer go to C:\Users\User\AppData\Local\CoopPuzzle\Saved\SaveGames Remove the save file inside and store it (you might need it if you dont want to run it all again). goto C:\Users\User\AppData\Local\CoopPuzzle\Saved\Crashes and delete all crashes same for C:...

Me and my coop partner did everything and he got all of the achievements meanwhile I got stuck with 7/13 and Ive tried everything that comes to my mind (hosting, non host, deleting saves from appdata, verifying integrity of files and reinstalling) but nothing unlocks achievements for my thief run...