sudo chown (username) (file name)
See if that helps.

She has one with built in security and it probably needs a password. Do
you know what she did no first use.

My wife uses windows exclusively so I know there are no permissions on
her USB drive. I used it a week prior and added some files to it with
no permissions needed. But that day it was asking for permissions and
telling me that it was my USB drive but that I did not have the
permissions. After I rebooted, I tried it again and then it is worked
ok without asking for permissions. Gremlins, I suppose!