Robocopy - Exclude Existing Files

robocopy_exclude_existing_files.cmd

robocopy c:\Sourcepath c:\Destpath /E /XC /XN /XO

:: /E makes Robocopy recursively copy subdirectories, including empty ones.
:: /XC excludes existing files with the same timestamp, but different file sizes. Robocopy normally overwrites those.
:: /XN excludes existing files newer than the copy in the source directory. Robocopy normally overwrites those.
:: /XO excludes existing files older than the copy in the source directory. Robocopy normally overwrites those.
:: With the Changed, Older, and Newer classes excluded, Robocopy will exclude files existing in the destination directory.

@mpniel robocopy is a syncronization utility. That means that not copying files that are different would be strange. In that context, not comparing files at all is the weird edge case. The ability to turn off each type of difference check one at a time is the more useful scenario.

(I say that having come here looking for a way to turn off all the checks in one go)

#ALL files were copied and no OVERWRITING ONLY IF SOURCE FILE WAS ACCESSED BEFORE THE LAST TIME DESTINATION FILE WAS ACCESSED

IT MIGHT NOT WORK FOR EVERY CASE

$robocopyArgs = "/log:D:\robocopywithnflndllogs\output.log" + " /XO /XX /S /E /ZB"
Start-Process -FilePath "C:\Windows\System32\Robocopy.exe" -verb runAs -ArgumentList "$source", "$destination", $robocopyArgs -Wait

#neither extra files at destination should be deleted
#neither files at destination should be overwritten (meaning: if files at destination are edited then should not be overwritten)
#all extra files at source should be copied to destination

/xn Source directory files newer than the destination are excluded from the copy.