I have a robocopy command that I use to backup files from a local Windows based home server to an external hard drive.

The command I use to backup and log files is as follows:

robocopy "F:\DATA" "W:\DATA" /mir /r:2 /w:10 /MT:32 /tee /log+:robocopy.log /ts /fp /np

It provides the log data I want without adding extra stuff.

But I frequently see *EXTRA FILE entries that join two file paths.


*EXTRA FILE  3.8 m 2020/02/12 10:42:32  *EXTRA FILE   2.1g 2020/01/31 11:42:52 

(all on one line)

When it should look like this on separate lines:

*EXTRA FILE  3.8 m 2020/02/12 10:42:32  W:\DATA\IMAGES\PICTURE001A.JPG
*EXTRA FILE  2.1 g 2020/01/31 11:42:52  W:\DATA\VIDEO\VIDEO423B.MP4

Most are correct, but just some files it shows like this. Any idea why and how to correct this?


  • This looks like a classic multi-threading issue to me. Two threads go to put a log in the output at the same time and interrupt each other. If I am right, it is a RoboCopy issue and there isn't much you personally can do about it. Maybe update to the latest version (if you aren't there already) hoping that they fixed the bug. Maybe play with the number of threads to see if the problem gets better or worse. My bet is that if you gave it only one thread the issue would go away, but you'd, of course, take a performance hit. – Frank Merrow Mar 27 at 0:42
  • Thanks @FrankMerrow . I hope I am using the latest. I'm using Windows 10 Pro updated to latest version, unless there's a way to install an updated Robocopy? I'm not aware of any? – HTWingNut Mar 27 at 1:57

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