InDesign Package Empty when Unzipped

Hi, I don't know what seems to be going wrong, but here is my issue:

I'm working on an InDesign document on a Macbook Pro and trying to share the InDesign package with a colleague who is working on a Windows PC. When he unzips the InDesign package I sent him on his computer, the resulting package is always empty. He's able to view the contents of the zipped package before unzipping, but he isn't able to actually open the files without unzipping, which always ends in an empty folder.

I've tried sending it to him through Dropbox, a flash drive, and a shared network drive folder. All of these produce an empty InDesign pakage on his end.

What is going wrong? Is this an issue with the unzip tool on his end, or is there something else I'm overlooking?

My other colleagues seem to be able to open the files on their computers so I'm unsure of exactly what's going on with his.

Any help would be greatly appreciated!