Files with the extension .DUP0 are duplicates of existing files and are commonly found on Android OS devices.

Commonly found in media folders such as photos, video and music - these files can be safely deleted as they are simply duplicates of files that already exist.

It is reported that certain syncing software (responsible for keeping your media library in sync with your computer's media library) is primarily responsible for creating these files. In these cases, sometimes performing a re-sync with your main library can automatically remove any duplicates.

If duplicate files are found on an sd-card, it is possible that unmounting the card and then remounting the card can resolve any duplicate file issues.