How do i fix my print?

[weednation12 0]

I have printet a lot of stuff since i got my Ultimaker, but sometimes it just fucks the print right up.

What am i doing wrong?

[IRobertI 521]

Could you be a bit more specific? "Sometimes it fucks up" isn't very helpful. Does it happen on all models? Does it happen at the same spots (z-height)? Does it happen with all materials? Have you noticed anything else besides what you took a picture of? etc

[yvest 18]

I agree with IRobertl that a bit more info would be helpful :-) but looking at the picture I wonder whether you might have some floating layers in your design making the printer print in the air. It might be just 1-2mm which is not supported making the filament not stick to the layer and getting all over the place. More info will for sure bring us closer to a solution. Good luck!