I have an old CTC Bizer with dual extruder and Sailfish 7.7
Slicer: Makerbot Desktop; I couldn't get anything else to work
I did some test prints which were successful.

Now I wanted to do a two-color print.
I sliced an object in Makerbot Desktop and send it to the printer.

After heating, both extruders are primed succesfully.


It then moves to X until the end (on the side without an end stop) and doesn't stop.
Which causes the belts to skip to infinity.
With Single Extrusion it does this too, BUT after 2/3 jumps of the belt it notices and starts printing.

What can I do against it?