Printing in mid air problem

[hcdbey]

Using Rostock Max V, MatterControl 1.6.1. As the printer starts printing, after about one inch, the hot end lifts off of the bed and starts extruding in mid air. It continues to raise up at about a 15 degree angle and if I don't turn the printer off, the hot end crashes into the Z tower.

I can work around this by doing 3D view, edit, rotate, (but don't actually do any rotation) and then align with bed.

Prior to doing the align with the bed, if I rotate the view of the bed, not the part, and try to look for a gap between the part and the bed, it looks like there is no gap.

This doesn't happen with other parts.

Does anyone have any ideas about what is going on?

[Mac The Knife]

Which printer? V1, V2, or V3? Anyways, without a picture, or description of the part, I can only speculate that you are trying to print a large diameter or wide model. If that's the case, you may be traveling to fast and its skipping steps. If you reslice the model, slow down the print speed and it still does it, then I would check for a mechanical problem.