I am trying to set up mirroring with robocopy to backup directories to micro-sd cards, as:

ROBOCOPY "C:\test" "E:\test" /MIR /COPY:DT /Z /W:5

This works fine for the most part except for PDF files for some reason, halting the process and returning the error:

2019/05/24 16:13:41 ERROR 87 (0x00000057) Changing File Attributes 
The parameter is incorrect.

Copying manually is not issue, both volumes (C: NTFS, and E: exFAT have been checked to be ok) and I have tried to circumvent it with all kinds of flags with not resolution. Does anyone have any ideas what the issue could be?

1 Answer 1


I had this issue and in my case it was due to the timestamps on the source file being out of supported exFAT range (the year was something like 1701). Ended up fixing them with Timestamp Clamper. (edited to include the name of the tool)

  • Your link has suffered link rot, so your answer is now useless.
    – KeyszerS
    Dec 21, 2021 at 17:24
  • 1
    @KeyszerS - Whoops, my bad, should've given the name instead. It's something called Timestamp Clamper. The link works for me though. It's also the same link as on their homepage.
    – Angstrom
    Dec 22, 2021 at 9:01
  • This answer is spot on. I used touch from Git Bash to change the file datetime, or you can use any of the solutions at superuser.com/questions/10426/…
    – wisbucky
    Feb 7, 2022 at 22:25
  • I found the spec of exFat requires year 1980 and above, indeed: learn.microsoft.com/en-us/windows/win32/fileio/…
    – knocte
    Jun 9 at 7:24

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