Not all files were copied to My Passport

When the initial backup was performed, certain file types (the specific ones that I wished to backup, actually) were not present on the hard drive. These are video files saved in a folder in “My Pictures” on my PC. Any idea why they wouldn’t backup or why I cannot get them to transfer/copy to My Passport? Thank you in advance for any help.


What type of files? Can you post the files extensions?