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I am trying to use Robocopy to sync (/IMG) a folder on my PC and a shared network drive.

The problem is that the file attributes differ by 1 sec on both locations (creation,modified and access). So every time I run robocopy, it syncs the file again...

BTW, problem is the same if I delete the target file and robocopy it from new... still, new file has 1 sec different properties.

Env Details:

  • Source: Win 7 64 bit
  • Target: WD My Book World Edition NAS 1TB which takes its time from online NTP (I don't know if file system is FAT or not)
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migrated from Dec 27 '10 at 1:02

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Wouldn't this question be more appropriate on serverfault or superuser ? – Sylvain Defresne Dec 25 '10 at 17:43
It may be because the two machine have a diverging clock. Try to synchronize the time with the same NTP server on both machines. There is also an option to robocopy to allow small divergence on the timestamp. I think this is robocopy /MIR /FFT ... – Sylvain Defresne Dec 25 '10 at 17:45
up vote 0 down vote accepted

If the target filesystem is formatted for DOS, i.e. the FAT filesystem, it can only store modification timestamps with a resolution of two seconds, as documented here: File Times

Sylvain's suggestion to use robocopy's /fft option should address the problem.

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/fft solves the problem. but it is a external drive, so I am not sure about FAT or not being the issue. – csmba Dec 25 '10 at 20:40
External drives are actually FAT formatted for compatibility quite often, so it's pretty likely. – houbysoft Dec 27 '10 at 1:06

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