Hey there,Please make sure you are running Steam, Rainbow Six Siege and the Uplay client with administrator rights.[support.ubi.com]If this does not resolve your issue, please try reinstalling the game.If you continue to experience issues after this, can you please create a case on the support website[support.ubi.com]Thanks.- Ubisoft Support

Originally posted by Ice:

Originally posted by RedSkorpion: Did you try starting it from uplay itself, it always takes quite a while for me aswell when i start it from steam. Open up your task manager to look for the task maybe its bugged out.

I cant launch it from uplay

Have you tried the troubleshooting steps provided? - Ubisoft Support