An orphan file is a file once associated with a program that remains on the computer after a program is deleted or uninstalled. These files do not cause problems or harm the computer, but they occupy disk space and are never used.
How to find orphaned files
Unfortunately, detecting orphaned files is difficult because you'd need to know what files are copied to locations outside of the program folder and manually delete them. If you deleted a program folder instead of uninstalling the program, you can install the computer program again and uninstall the program to ensure all files are properly deleted. Otherwise, the only method to make sure a computer has no orphaned files would be to erase the computer and start over with a fresh install.