Michael McKinnon

How to do Windows Backups with Robocopy – Tips & Tricks

Michael McKinnon

I’ve been using a handy little Microsoft tool for many years now called ROBOCOPY which is a great command line tool for copying large sets of folders and files from one place to another, especially over a network.  It has a nifty network-restartable mode (/Z option) which means if it fails, you can just re-run the command and it will pick up where it left off – essential when you’re moving Gigabytes and Terra-bytes of data.  It’s also great for mirroring data between file shares on servers.

From a command prompt (usually with Administrator rights), here is how I use it:

robocopy /Z /E /R:0 /W:0 <source-path> <dest-path> /XD "Temp" "Temporary Internet Files" /XF pagefile.sys hiberfil.sys
Here’s a really quick run-down of the switches I use and why:
  • /Z – this is the network restartable mode, it checks the destination to see if the file already exists and skips, and also provides a % counter as the file copies
  • /E – this tells it to copy sub-folders, including empty ones
  • /R:0 – the default for Robocopy if it can’t get a lock on a file is to retry 3 times, but if it can’t lock a file for reading the first time, it usually never will, so I set it to zero.
  • /W:0 – this is the number of seconds to wait if retrying, because we don’t retry I just set this to zero.
  • <source-path>, <dest-path> should speak for themselves
  • /XD – this is to exlude folders such as “Temp” and “Temporary Internet Files” which I never bother backing up, they should never contain anything useful.
  • /XF – this is to exclude certain files, such as the system Paging and Hibernation files which are really big and are re-created if you ever restore a system.

Why not use XCOPY instead?

Good question, I just got so used to using ROBOCOPY and the few times I tried XCOPY it didn’t seem to do what I wanted as reliably.  And as it turns out Microsoft agrees with me, and has actually deprecated Xcopy in favour of Robocopy – so stop using Xcopy today!  Robocopy is now shipped by default with Windows Vista/7 and Server 2008 and onwards; it used to have to be installed separately from a Resource Kit.

Here’s a big tip that you might come across

There is a known issue with some Windows Vista/7 machines (usually the ones that have been upgraded from a Windows XP install) – you’ll get an infinite loop problem during backup that will cause the “Application Data” folder to be nested so many times that it will eventually cause a “file name too long” error in the NTFS path.

This problem (read more here) is simply because there is an NTFS “junction point” in the file system and ROBOCOPY follows that point around and around causing this issue.  The solution BEFORE you backup is simply to add this switch to your ROBOCOPY command:
  • /XJ – Exclude NTFS junction points, to avoid the endless “Application Data” folder nesting on some Windows Vista/7 machines.
If you already have an old backup that had this occur, it can be really hard to delete the old backup when the file names stored are too long, and about the quickest method I found was to run this quick one-liner in a command window:
for /f "delims=" %X IN ('dir /x /b /s "Application Data"') do ren "%X" "ad"

Note: the command above is quite destructive so please only run it over a backup set that you’re trying to delete, but can’t because of the “file name too long” error.

You just CD into your backup path that you’re trying to delete, and run this command.  You will see errors, but just use the up arrow and enter key on your keyboard to run the command multiple times – each time it runs it will rename another couple of “Application Data” folders to “ad” and so forth – keep running until the command returns “File not found.”  Then you’ll need to trying deleting your backup set and it should now work!

A note about full Windows machine backups and Robocopy

Robocopy is great for general backups of data, and with a bit of time you could re-install Windows and restore a machine pretty well with a Robocopy backup, however, if you’re intending to be backing up a Windows machine with the intention of having a quick restoration time in the event of a catastrophic failure you should be using an image backup tool.  Perhaps something like the built in NTBACKUP tool, or even ShadowProtect which is awesome for Windows Servers.