I was having the exact same problem as Tirapiedras - the verbose log would fill up with "permission denied" errors and it would get stuck at 30% and either crash or hang indefinitely. His report was the only other example I could find that matched my experience so I sent him a PM yesterday to reassure him that he wasn't alone. He replied while I was at work today with a solution: launching the patcher from the terminal using sudo! I can't believe I didn't think to try it myself, but thanks Tirapiedras, you solved a problem that had me stumped for several days!