Same problem. Down loaded all vehicle updates. Tried from all angles (menu system is loaded with false results).  Looks like multiple programmers worked on the system and did not come up with a seamless interface.  Out of the blue, the Maxifix came to life.  There was no entries that applied to a MB clk350.  Finally was able to get the J2534 programer to start working but the ecu codes could not be found on their servers.  I'm not holding my breath waiting for the fix. I had copied all the ecu codes from the unit and sent those to them with the data logger app.  Good luck.