Right click on the file - Properties - Security. The check boxes will show Full Control, Modify, read & execute, read, write and special permissions. The files could be set to read only.
After an upgrade from Win 7 to Win 10, my Vaio all-in-one PC will read the directory of a FAT32 formatted USB stick, but when any attempt to access any file (to open, copy, modify etc) I get the "File Access Denied" error "You'll need to provide administrator permission to copy this file". I AM the administrator and have tried all the methods of Taking Ownership and trying to modify the Security on the files. None works, as FAT32 files don't have security!! The stick works perfectly on another Win 7 machine, a Mac and used to work on this PC. Anyone have a solution?