I have a C-Drive (Windows 10) and several EHD's (external hard drives).

The EHD's mirror what is on the C-Drive, I use the EHD's to back up the exact data, the exact number of files, that are found on the C-Drive.

Problem: Sometimes my C-Drive might have a folder that has way more files in it than the EHD does. For example, the My Pictures folder located on the C-Drive

might have 1,100 files in it

and the same folder located on the external hard drive might have less,
950 files in it.

Is there a procedure (or a software program) that will

quickly find, highlight, and point out

the 100 outstanding files so a person can transfer them over to the EHD?

My EHD's are remotely stored in a safe deposit bank at a chosen bank. I swap them out, or rotate them, about once a week.

Please dumb your answer down, way down, if you're a code king or code queen, because I'm a simple person who works in a deli, thank you

My OS: Windows 10