Materials do not transfer onto external HD

Okay, I’m working on a project with a team for my class, and for the sake of my own time understand that for one reason or another I am not able to use version control tools like diversion.

The way we are combining our shared project is by importing it onto a drive and migrating it bit by bit. Yes, I know that’s a nightmare. For some levels, this works great. But we are running into an issue where with one specific level, material information and textures appear to not transfer over properly?

Basically, the landscape appears to be black like tar, missing its different landscape material layers. Some of the other objects in the scene do as well. Any method to remedy this? The level appears fine on my teammates computer. Thanks in advance!