It keeps saying part files are missing even after I separately uploaded all parts.
I'm with GrabCAD Support, and I wanted to know if you are still experiencing this issue. If so, please provide me with a little more information, and I would be more than happy to assist you. Also feel free to reach out to us at email@example.com, where you are likely to get an answer from us sooner. Thanks!
Zip the folder containing all the files, then add the compressed file to your answer.