Files names are changing when I drop them into Box.com

I am having the issue that when I drop or upload files into Box.com that it will change some of my files name or result in them not uploading them from all one folder that I am trying to upload. I will then have to drag each one and hope that the file name stays the same. If the file name doesn't stay the same, I have to copy and paste the name from my original file on my desktop. Why is this happening? Thank you.