Backing up files on Windows without any additional software is best done by Robocopy. Robocopy is short for “Robust File Copy” and is a command-line utility for file and directory copying for Windows. Using Robocopy is the easiest way to backup files in Windows without using any additional software.
The command is robocopy. Basic usage is:
robocopy <source> <destination>
To use it to back up files, there are two general approaches (more exist but this is a good start):
Mirror Copy
A mirror copy will delete any files not found in source from the destination. It will essentially mirror everything in the source to the destination. This is useful if you want a
robocopy /S /PURGE C:\MyLocalFolder D:\Backup_Mirror
or, more simply:
robocopy /MIR C:\MyLocalFolder D:\Backup_Mirror
Accumulation copy
An accumulation copy won’t delete any files in destination that are not in source. The destination will essentially accumulate files over time that were copied from previous copies. This is useful for workflows that the source files would get deleted but we would like to keep backup. The /S option will copy subdirectories, but not empty ones. Careful not to mix them up!
robocopy /S C:\MyLocalFolder D:\Backup_Accumulate