Files missing from My Passport Ultra

Has anyone had any problems with files not being on your My Passport Ultra once you eject your disk from your computer?  I had thousands of files on the Passport HD and printed off a contact sheet of all the files, ejected the drive and moved it to another computer and there was only 1 folder on it.  Has anyone ran into this problem before and if so how can I avoid it happening in the future.  I had it connected to a Mac Pro Server computer. Any help would be greatly appreciated. Thanks,

Welcome to the Community.

How were the files copied into your hard drive?