Windows 10, version 1809/190x: robocopy extensions

[German]In Windows 10 version 1809 and version 1903/1909 Microsoft has added some extensions to the robocopy command with the preview updates of September 16, 2020. To my knowledge, Microsoft has not documented anything so far.


Robocopy extensions

On September 16, 2020 Microsoft released several cumulative updates as previews for Windows 10 versions 1809, 1903 and 1909. I had reported about this in the blog post  Windows 10 V1809/190x: Preview Updates (September 16, 2020). In the change list you can also find the following note.

Adds new functionality to the robocopy command.

Microsoft has, as far as I've noticed, nothing documented so far regarding possible extensions. The documentation page for robocopy was last updated on June 7, 2020. My Twitter request to the Windows Update Social Media Team has so far no result …

The robocopy extensions

German blog reader jss has left the following information as a comment – so the new commands and options are probably fixed..

/IM:: Contains modified files (different modification times).

/LFSM :: Operation in "little free space" mode, allows copying, pausing and resuming (see comments).

/LFSM:n [CMM] :: /LFSM, specifies the floor size in [K:Kilo,M:Mega,G:Giga] bytes.

Besides that, the current 2004 robocopy help, according to the comment of jss, mentions two more switches that the 1809 does not throw out even with the update:

/SJ :: Copies connections as connections instead of as connection targets.

/COMPRESS :: Requests network compression during file transfer if necessary.

The robocopy compress command has been mentioned by Ned Pyle within this Techcommunity article.


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One Response to Windows 10, version 1809/190x: robocopy extensions

  1. Kai says:

    /IM can be very useful:
    Robocopy wouldn't copy a file it considered as 'changed'.
    [Oddly enough, there is no /IC switch, only /XC,
    but RC doesn't copy 'changed' files anyway, even without /XC.]
    Before, the files were considered 'same', so I could force the copying using /IS.
    But now, with the file considered as 'changed', coping it was not possible!
    Neither /IS nor /IT did work (nor omitting /XC, of course).
    The solution then was the new /IM !

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