I'm trying to open SMBX2 Beta 4, but it simply refuses. No error message, just completely refuses to do anything. I have tried re-installing it, but it's still not co-operating.
I'm having the same issue and found a potential fix. It might be your antivirus that's flagging those specific files and either deleting them or quarantining them. Adding those files to the "exceptions" tab of my antivirus fixed the issue.