Robocopy Incorrectly Detects Files as Newer When Copying Between Different File Systems

Posted on August 20, 2010 10:40 PM

I came across a problem in one of our automated Robocopy command scripts when copying files from NTFS to EMC Celerra file system.  The problem was that every time Robocopy was told to copy files to the EMC Celerra over the VPN, the files were always detected as “newer” on from the originating source.  This caused Robocopy to copy every single file from our network to the remote network each and every time. 

I came across a command line switch for Robocopy: /FFT : Assume FAT File Times (2-second date/time granularity).  So what this does is force Robocopy to use FAT style time stamps which are 2-second granularity.  It allows enough flexibility to account for the way the time is recorded when doing a file copy from NTFS to another file system. This is needed when going between and NTFS and Linux/Unix/FAT or emulated file system.

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Comment by me

September 1, 2010 3:24 AM

Thx; this works greatly !

Comment by fer

November 19, 2010 3:41 PM

Awesome, thanks! Why this is documented in the /? output I'll never know.

Comment by Mike

January 18, 2011 8:09 AM

Wow! Thanks... I've been moving files between a Windows machine and a Linux based NAS, and the source files are always recognized as newer... even thought they aren't. This fixed it! Thanks VERY much.

Comment by Matt

April 15, 2011 3:38 AM

Yes, the switch kind of works, but even with it, there seem to be cases - perhaps system related where it still incorrectly detects the file as newer. I suppose however, you really want to be certain that the backed up file is valid, so the only harm in copying files unnecessarily is if you have TB's of files (which is my situation).

Comment by Jason

September 13, 2011 11:50 AM

Awesome!!! This solved my problem and is worth the praise! I was doing the same type of copy from Windows 2008 to EMC NX4. Now my scripts fly :)

Comment by Seb

October 21, 2011 10:57 AM

Thank you VERY much! It's more than helpfull!
Used from Windows 2000, 2003 to EMC NS480, it worked like a charm!

Comment by James

October 28, 2011 3:06 AM

Thanks this fixed a bkup robocopy to my Snapserver which is Linux based.

Comment by David Naquin

February 29, 2012 10:52 AM

I've been racking my brains for 2 weeks now trying to figure out why some files re-copy as new and others don't.

This totally solved my problem . . . MANY, MANY, THANKS

Robocopy developers . . . ya'll need to expound upon this a little better in the documentation

Comment by Daz

April 14, 2012 4:16 AM

Solved my problem using robocopy from Win7 laptops to my home Mac Mini server !

Comment by Nichlas

April 20, 2012 9:46 AM

This solved my problem using robocopy on Win7 to copy files to my Ubuntu SAMBA server,

Comment by Carsten Giesen

October 20, 2012 9:39 AM

Thanks, thats resolve my problem...

Comment by Paul

January 15, 2013 8:58 PM

Fixed an issue for me when copying between a 2003 and 2008 R2 File server! Cheers

Comment by Vince

January 18, 2013 4:41 PM

This fixed my issue. Was copying from CIFS share to Linix cifs share over WAN link and was getting newer each time and it was recopying the files over and over. Added the /fft and now it's showing "same" for the files that are already copied. Awesome.

Comment by Steve

January 28, 2013 10:01 PM

Just to be clear - It seems to be case sensitive - Make sure you use /FFT not /fft... Otherwise works great.. Using it to copy to a linux based 'UNRAID' server

Comment by Sergio

February 1, 2013 10:13 AM

Just another thank you, I was looking for a solution for a few weeks.

Solved my issue between Windows 7 computers and a NAS Server (D-LINK DNS-325)

Comment by Richard

February 5, 2013 7:40 PM

Kudos to you from me as well. Been banging my head against a wall backing up from an XP machine to a SAMBA NAS drive using ROBOCOPY. Your advice fixed the problem. Thanks!

Comment by JL

February 6, 2013 7:48 PM

Cherry! It worked. Thank you.

2008 Server -> Celera

Comment by jgaskell

February 13, 2013 12:27 PM

Many Thanks! Corrected my issue going from NTFS to a Linux based network drive.

Comment by Ipop

June 10, 2013 3:02 AM

Ce paramètre a corrigé mon problème de recopie systématique de fichier entre le serveur de fichier Windows 2003 et Serveur CIFS sous EMC
Merci !

Comment by MDgeek

June 14, 2013 11:21 AM

Thanks a lot for this info. I frequently get this questions from our help-desk people and I was wrongly telling them that [i]"file must have changed"[/i] therefore, copy it again. We are taling of several Terabytes.

Comment by Firewalker

September 26, 2013 5:51 PM

Wow, two hours lost trying to troubleshoot why my differential robocopy from windows server to Emc vnx cifs server was copying what seemed to be identical source to destination files. This needs to be published onto EMC's knowledge base as I could not find anything when I originally searched.

Thanks once again.

Google makes me look good!

Comment by resmartin

September 28, 2013 1:46 AM

I basically use Long Path Tool only.

Comment by eLeL

October 16, 2013 4:23 PM

Thaaank you!
Just to add, in my case (copying files and directories from sbs 2008 to NAS), not only it recognized every time file as newer, it also didn't copied some folders!

Now everything works just fine!:-)

Comment by Sakari

December 25, 2013 6:24 AM

You can actually see the slight difference in the file time stamp, you launch PowerShell and type the command (for both the original and copied file):

(dir yourfilename).LastWriteTime.Ticks

So NTFS has one digit more, which in the NAS is probably always zero.

Comment by Trane Francks

January 27, 2014 2:55 PM

Dang. This /FFT business was driving me nuts. Thanks for supplying the answer. Virtual beer's on me!

Comment by twaldau

February 10, 2014 1:10 PM

Great! Also working with Win7 64bit and WD MyBook.

Comment by Jon Garrett

March 19, 2014 10:26 AM

Thanks very much for this had exactly the same issue!

Comment by esteban

March 30, 2014 2:00 PM

I'm using robocopy to /mir files from my local pc to skydrive. The /XO is detecting files always as newer, even though I'm using /FFT switch. Has somebody a solution?

Comment by john mcaulay

April 9, 2014 10:26 AM

THANKS! FIxed my problem of copying from Storage Server 2012 onto a Linux based NAS box.

Comment by Ashish Grover

January 16, 2015 4:01 AM

Thanks You.

Comment by Michael Bissell

February 12, 2015 4:10 PM

BLESS YOUR SOUL! I always used a DOS script with Robocopy between my to Windows laptops, but one just died and I bought a Mac Book Pro. This switch fixed my problem of always copying all files as newer from the Windows laptop to the Mac. Thank you very much!

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