Cura builds walls

[Ballowii 0]

It's my first time printing and I made a Modell in Blender of a trophy which i seperated in 4 parts. In Blender when I select Non Manifold it selects no vertices and the side https://makeprintable.com wrote that it had no errors.

But when I load it in Cura, it suddenly builds walls where non should be and closes a drillhole I prepared.

Which settings do I have to change to stop it from doing that? I allready checked "keep open faces" which didn't really change anything. Or is this some kind of support wall, which I must cut away afterwards ?

https://www.dropbox.com/s/m7et9o3uxqrpcrb/henkel.gcode?dl=0

https://www.dropbox.com/s/otas2y8oddcv85p/henkel.blend?dl=0

[gr5 2,210]

Go to expert settings and under "fix horrible" uncheck everything - particularly I think "type A" is checked. Uncheck that. This will fix your drill hole issue I think. I assume this is cura 15.* as that is what the screen shot looks like.

If that's not the only issue then try viewing your part in xray mode and check for any red areas. red is bad.

Also in cura consider right clicking on the object and try to split it into 2 different objects. Maybe? I'm not sure if that is what you want.