This is way late but.... I had this same exact problem and I sat here for literally days trying to fix it. I tried everything; older versions, deleting contents, deleting the sandbox in the computer file, etc.. Well, after doing a shit ton of research, I learned that for some God forsaken reason, on windows 8.1 (at least on this laptop I'm using), it doesn't put the launcher and game files into the sandbox, it tries running it outside of it. So if you go into the sandbox file itself, and manually put the game into the sandbox it "should" work. I advise though, before doing that, delete all the files and content of sandboxie and redownload for a clean start. Otherwise you'll go crazy because it tends to throw the game files anywhere and everywhere. Why? I don't know. The error I was getting was SBIE2224 and SBIE2225, of which the sandboxie forums had no description of like they don't even exist/happen, yet they're there.