At a glance
Tom Clancy's Rainbow Six Siege won’t run on a Mac: it is protected by anti-cheats BattlEye, FairFight and R6 ShieldGuard, which do not let it start on a Mac.
Steamstore
single player, multiplayer, co-opmodes
fullcontroller
Tom Clancy's Rainbow Six Siege came out on Steam on 1 December 2015, made by Ubisoft Montreal.
Why it will not run
The anti-cheats BattlEye, FairFight and R6 ShieldGuard block the game on Mac. Uncork settings cannot fix that.
Can you play on a Mac another way?
Only in the cloud — for example GeForce NOW, if the game is there.