Errors when printing part

[beemergb]

I am having a problem with my Simplify 3D program , when I try to print this part lying down its looks like this ! With parts missing and parts I havent even drawn ! And when I print the part standing up its ok ! Can you help me please , thank you Harry

[horst.w]

If you attache the FACTORY-file, someone surely can help!

horst.w
GER

[dkightley]

An alternative to try if you use Windows 10.....

Load the stl file into the Windows app 3DBuilder. If it prompts to repair the file....which I think it will do....answer Yes, then Save as a 3mf file of the same name. Note you'll not be allowed to save it as a n stl file. Finally load the 3mf file into S3D.....and the shape will probably slice correctly.