[Jimmy Cao]

Originally Posted by Akademee

Thanks, I repaired Solidworks and it seems to be working fine, I did find something interesting though, I am not sure if this should be worth noting as a bit of an FYI, but I found that Solidworks can open an .stp file as a part, however it cannot insert an .stp file into an assembly. I had to save the .stp as a Solidworks part before I could insert it into my assembly.

Thanks for your help everyone!
Akademee

Glad it worked out!

When Solidworks opens a .stp file, it doesn't just "open" the file as is. It generates a .sldprt (or a .sldasm and a few .sldprts). You'd need to save those files before you can insert into an assembly. Its just a feature of the software; I think all CAD platforms behave similarly.