Robocopy Commands: Data Migration, Folder Sync, and More

Robocopy is one of the most-used command-line utilities to copy large volumes of data in Windows. It’s such a popular tool because of how powerful it is. But with all that power comes complexity. In this guide, we will break down all that complexity and provide a complete tutorial on using this useful tool.

Robocopy is a Windows command-line utility that’s been available since Windows NT. It’s a replacement for the less versatile xcopy utility. It allows you to specify a drive path or server path to copy/move files at a command prompt.

The version of Robocopy as of this writing is up to 10.0.18. This is the version I performed my testing on.

Robocopy provides a slew of features you can leverage to perform efficient and fast file copies and moves. It can:

• Copy files over a network with resume capabilities
• Can skip NTFS junction points causing failure typically from infinite loops
• Can copy file and directory attributes preserving timestamps
• Can copy NTFS permissions, owners, and auditing info
• Can copy directory timestamps
• Can copy files in ‘backup’ mode to ensure files are copied even those rights have been denied to the administrator
• Automatic retries
• Can sync two folders
• Is smart enough to skip files already copied
• Can copy paths larger than the 256 character path limit
• Perform asynchronous copies using its multithreading ability.
• Returns standardized exit codes for use in scripts

As you can see, there’s a lot to to copy. I wanted to cover everything you need to know about this handy tool.

Common Robocopy Syntax Reference

Why such a long blog post on a single utility? Just feast your eyes on the tables below. You have a lot of options to copy or move files with robocopy! You will more options in the individual sections.

These tables were built from the help syntax returned from robocopy /?. They’ve been broken up into more meaningful sections, added to over time, and cleaned up to provide more useful info.

Source Options

Destination Options

Copy Options

Monitoring Options

Understanding Robocopy Behavior

I’ve now completely blew your mind with all of the potential syntax options available to you. Let’s now see all of the different combinations of how we can use this syntax.

I could provide you an enormously long list of robocopy commands with an ever-growing number of switches. But I think it’s better to teach you how to fish. Let’s go over how to put sense out of all of these options.

Robocopy Only Copies Entire Directories

Every robocopy execution will have a source and a destination directory. Robocopy copies and moves files by entire directory. It’s not possible to explicitly copy a single file with robocopy. Use copy or PowerShell’s Copy-Item for that.

However, you can robocopy single file with the right filtering which you’ll learn about below. To robocopy a single file file, specify the source and destination directories immediately followed by the file name in the source.

> robocopy c:\src d:\dst copythisfile.txt

Syntax Depends on the Environment

Also, the options you provide to robocopy will depend on the environment. You’ll need to answer a few questions when trying to figure out which options to use.

• Will you always be copying to an empty directory?
• Is it possible files may already exist in the destination directory?
• Will you be copying terabytes of data or just a few megabytes?
• Will you be copying files over a network or locally?
• …and more.

If there are no files in the destination file directory, you shouldn’t care about options that overwrite files. If you won’t be copying files over the network, don’t worry about those options. Explicitly define your current and potential future circumstances your environment will be in.

Recognize Default Options

Robocopy uses a lot of options by default. You can pick them out by looking at the tables above. It also provides a handy output to every time you run the utility.

You can see below that when I ran robocopy with its most basic options (the source and destination folder), it automatically used some options. Understanding the default behavior is important.

Reference the options you see in the output with the option explanations above and you’ll understand exactly what robocopy is doing under the covers.

Understanding What Robocopy Commands can Do

If you’ve used copy or PowerShell’s Copy-Item cmdlets, you’ve probably specified a source and destination and went on about your day. There’s not a whole lot of options you can configure there. These robocopy commands have a default behavior.

But robocopy, on the other hand, understands a lot more and gives you the flexibility to tweak the behavior as much as you want.

It’s important to know robocopy isn’t just aware of the concept of a file or directory. There’s a lot more to a filesystem than that and robocopy supports just about everything.

A file sitting on a filesystem isn’t just a dumb object with a single purpose. There are many different attributes and things that go with the concept of a file. For example, a file has attributes such as:

• a timestamp (written, modified and accessed)
• NTFS ACL
• an owner
• NTFS auditing information
• hidden flag
• archived flag

When you copy or move a file, you have the option to bring all of that stuff along with it, if you want.

Understand that when you run robocopy, you’re not just copying a file, you’re also potentially copying all of the other information with it. It’s important to realize that and to account for it in the options you provide robocopy.

The Basics: Performing WhatIf Scenarios

If you’ve got a huge file server somewhere you’d like to migrate and don’t want to take any action yet, you can use robocopy to return what it would have done.

Using the /L option, you can tell robocopy to enumerate all of the files and/or folders you specify and return a list of files it would have copied/moved.

You can use the /L option with any other option. This is a great way to return all of the options robocopy would have used (default or not). It will give you an overall view of what robocopy will do given the options you provided it.

The Basics: Copying Files

The most basic use of robocopy is using a source and destination directory with no options.

> robocopy C:\src C:\dst

This option will copy all files (excluding subfolders) from C:\src to C:\dst.

You can also copy everything including subfolders (empty or not) and NTFS permissions. This is, from what I can tell, the method to literally copy everything there is about a directory of files to another directory.

Below I’m copying all NTFS ACLs, file owners, subfolders (including empty ones) and all file attributes. All of this is made possible with just the /E option to include all empty subfolders and  /COPYALL to catch the rest.

> robocopy C:\src C:\dst /E /COPYALL

The Basics: Moving Files

Moving files transfers files from one directory to another just like copying does. The only difference with a move operation is that the source files are removed after the copy.

To delete files/directories from the source after copying, use the /MOV option. This will remove all files in the specified directory (no subfolders).

> robocopy C:\src C:\dst /MOV

You can also use /MOVE to move all files and subfolders.

> robocopy C:\src C:\dst /MOVE

The Basics: Syncing Files

Robocopy allows you to sync two directories. This means either ensuring all files in the destination directory are in the source directory and no more. /MIR will replicate data copying all files in the source not in the destination and delete files in the destination not in the source. Beware!

> robocopy C:\src C:\dst /MIR

Copying Files over a Network

If you’re copying files over a network, there are a few options that you should consider.

Robocopy allows you to copy files in ‘restartable mode’ using the /Z option. This means that if a file begins copying and fails midway, the copy can start again instead of failing completely. The /Z option is useful when the stream gets cut over a network.

Warning: Some have reported using /Z cuts performance by 1/4. Let me know your findings.

You can also use the /FFT option. This switch has been known to more accurately preserve file timestamps when transferring over a network. This option uses FAT file system timestamps instead of NTFS.

robocopy C:\src \\SRV1\share /Z /FFT

Using /IPG to Control Inter-Packet Gap

When copying files over a network, you can use the /IPG switch. This is also known as the inter-packet gap option. This option defines (in milliseconds) the frequency in which robocopy will wait between sending new packets.

Always use UNC Paths not Drive Letters

A reader on Reddit discovered the hard way to not use mapped drives as a destination directory. Instead, always use always use a UNC path. You might run into issues with the 256-character limit if you do. Check out this Microsoft doc for more information.

Robocopy Backup Mode (Robocopy /Z)

Robocopy has a option (/B) or as a backup to restartable mode (/ZB) which copies files in backup mode. What is “backup mode” anyway?

When you usually copy a file in Windows and hit a file that requires administrative privileges to access, you’ll receive an error indicating you don’t have permission. Even though you may be running as the local administrator, Windows won’t let you access it.

WARNING: There have been reports of corrupted server volumes when copying data to a Windows Server 2016 server with de-duplication turned on. When you use the /ZB switch, the result will be a dedup chunk store being trashed in the System Volume Information. The copied files will not be readable and will generate errors when trying to manipulate them. Serverfault link with more info.

Backup mode is a way to access files without worry about permissions.

Robocopy uses backup mode to use the SeBackupPrivilege for reading files and the SeRestorePrivilege user right to access any files it needs. This ignores any ACEs that would normally prevent you from accessing those files.

The SeBackupPrivilege and SeRestorePrivilege user rights are normally assigned to users in the Backup Operators and Administrators groups but sometimes they can get removed. Backup module eliminates that risk and temporarily grants the user executing robocopy those rights.

If you’d like to check to see if your user account has that right, you can run whoami /priv and both rights should be displayed.

Filtering Files and Folders

The large majority of the options available to you are to exclude files and directories many different ways. I’ve broken down all of the ways you can filter or exclude files and directories based on various criteria.

By File Name or File Extension

Filtering what files get copied/moved in a robocopy call is done using wildcards. You can use a wildcard to filter on files matching a specific file name string or extension.

For example, to only copy TXT files, you can specify *.txt.

> robocopy C:\src C:\dst *.txt

If you’d like to limit to only files starting with a, you could use a*.

> robocopy C:\src C:\dst a*

Y0u can also provide multiple sets of file name matches by separating them with a space as shown below.

> robocopy C:\src C:\dst a* b*

When you filter by file name, robocopy will show you the filter in the output.

By Directory Name

Robocopy allows you to filter items not just by file but by directory name too. Using robocopy /xd, you can exclude certain directories matching a specific name.

When copying multiple folders, use the /XD switch to exclude folders from the run.

> robocopy C:\src C:\dst /XD "c:\src\exclude"

By File/Directory Timestamp

Below you will find all of the robocopy options that will exclude files and folders based on various timestamp attributes.

There are two popular options to choose when filtering on things like timestamp; /XO and /MAXAGE.

/XO allows you to exclude files from copy only if they are newer than the source. Using the /XO option, you can robocopy only new files by access date.

> robocopy C:\src C:\dsc /XO

If you know the maximum age files will be, you can also use the /MAXAGE option. This allows you to specify in YYYMMDD format the older date a file can have before it’s copied.

> robocopy c:\src c:\dst /S /MAXAGE:20191001

Robocopy Jobs

You have seen that dozens of options are available to you. It’s easy for these options to soon become unwieldy. Thankfully, you have a better option than memorizing and ensuring all of these options are spot on every time.

Robocopy job files are text files containing one option per line. You’ll typically use robocopy to create these job files. Once created, you can then either use robocopy to modify them or a simple text editor.

You have various robocopy commands that work with jobs.

A typical job file created with robocopy has an RCJ extension and looks like the below snippet. This job file was created by running robocopy C:\src D:\dst /save:myjob. You can see that you can provide comments in the job file using :: which is most of what this file has.

Without comments, the file would only contain one option per line.

::
:: Robocopy Job C:\MYJOB.RCJ
::
:: Created by Administrator on Sunday, August 18, XXXX at 8:53:24 AM
::

::
:: Source Directory :
::
        /SD:C:\SRC\     :: Source Directory.

::
:: Destination Directory :
::
        /DD:C:\SRC\     :: Destination Directory.

::
:: Include These Files :
::
        /IF             :: Include Files matching these names
::              *.*     :: Include all names (currently - Command Line may override)

::
:: Exclude These Directories :
::
        /XD             :: eXclude Directories matching these names
::                      :: eXclude no names (currently - Command Line may override)

::
:: Exclude These Files :
::
        /XF             :: eXclude Files matching these names
::                      :: eXclude no names (currently - Command Line may override)
::
:: Copy options :
::
        /DCOPY:DA       :: what to COPY for directories (default is /DCOPY:DA).
        /COPY:DAT       :: what to COPY for files (default is /COPY:DAT).
::
:: Retry Options :
::
        /R:1000000      :: number of Retries on failed copies: default 1 million.
        /W:30           :: Wait time between retries: default is 30 seconds.
::
:: Logging Options :
::

Saving Job Files

Saving a job file is as simply as appending the /SAVE:<jobname> option to the end of your syntax. Replace <jobname> with the name of the job. The /SAVE option will create a file called <jobname>.rcj in the directory where you ran robocopy.

> robocopy C:\src C:\dst /SAVE:myjob

You must specify /SAVE as the last option. Any options specified after /SAVE will not be added to the job file. Also, note that even if an existing job file already exists, robocopy will always overwrite the existing one. Backup or version control your job files!

Note: If you attempt to use the /MT option when saving to a job file, it will not be in the job file. Let me know if you were able to get this to be included.

Using Job Files

Once a job is saved into a job file, you can then use the /JOB:<jobname> option to specify the job file to read from. Robocopy reads all of the parameters inside of the job file. It then executes just as if you provided the options directly on the command-line.

> robocopy /JOB:myjob

Creating a Job File Without Running a Job Using /QUIT

The purpose of the /QUIT option isn’t obvious. On the surface, you may think /QUIT forces a running to exit. Instead, /QUIT acts more like an option to prevent a job from running in the first place.

Officially, the /QUIT option “forces robocopy to terminate processing the command line”. However, it would be better explained as creating a job file without running a job.

If you use the /SAVE option, it will also run the job automatically. There’s no way to create a job file without first running the job. You could create the RCJ job file with a text editor or you could use robocopy do it by appending /QUIT to the end.

> robocopy C:\src C:\dst /SAVE:myjob /QUIT

Editing a Job File

Since job files are just text files, you could edit them with your favorite text editor or you could have robocopy do it for you.

You can edit job files using a combination of /JOB, /SAVE and /QUIT.

For example, perhaps you’d like to exclude all EXE files from your robocopy job saved in a job file called backupfiles.rcj. You’ve already created the job file and don’t want to overwrite the entire thing. You can add the new option like below:

> robocopy /JOB:backupfiles /XF *.EXE /SAVE:backupfiles /QUIT

Using Multiple Job Files

You can even combine the use of job files too. When specifying multiple job files in the same run, all of the options used in that run will be combined together.

For example, perhaps you have a large list of files to exclude from your backupfiles copy job. Open up a text editor, and add the following to create an exclude.rcj file.

/XF
    a.exe
    b.txt
    c.cer

You can then exclude these files from the backupfiles job like so:

> robocopy /JOB:backupfiles /JOB:exclude

Since the original backupfiles job file was already excluding all EXE files, the above run’s syntax would look be /XF *.exe a.exe b.txt c.cer. Robocopy combines all options into one.

Robocopy Templates and Using the /NOSD and /NODD Options

If you’re working with a lot of job files, you can build job files to accept parameters. Robocopy allows you to pass values from the command-line to jobs when they are run. A parameter isn’t a robocopy term but it fits well in this scenario.

You can build robocopy jobs to accept parameters by not specifying a source or destination directory either explicitly using the /NOSD and /NODD options or just not including a source and destination directory at all.

For a simple example, create a job file with no source or destination using the syntax below. This job’s intention is to copy all TXT and EXE files from a source to a destination directory.

> robocopy *.txt *.exe /SAVE:backupfiles /QUIT

On its own, this job will never work because there’s no source or destination directory specified.

When you create a job with no source and destination directory, the job file is automatically created using the /NOSD and /NODD options.

/NOSD           
/NODD
/IF
    *.txt
    *.exe
/DCOPY:DA
/COPY:DAT
/R:1000000
/W:30

The /NOSD options tells robocopy you did not include a source directory while /NODD indicates you didn’t include a destination directory. This job file is a “template” for other jobs.

But you can pass “parameters” to this job file to provide the source and destination directories.

To use the job file just created to copy files from C:\src to C:\dst, you can pass these directories directly on the command-line which will then be passed to the job.

> robocopy /JOB:backupfiles C:\src C:\dst

Asynchronous Copying (Robocopy /MT)

By default, robocopy only processes one file at a time. However, you can force robocopy to copy more files than at once by using the /MT option.

The /MT option allows you to specify the number of threads robocopy will use to copy files. The maximum is 128.

You can use /MT like so:

> robocopy C:\src C:\dst /MT:32

I’ve chosen 32 in this case as a baseline. I suggest starting at 32 to see how your computer and network handle things and adjust the threads accordingly.

Note that if you do use /MT, you won’t be able to use /IPG or /EFSRAW. For better performance, don’t output the log to the console. Instead, use /LOG.

Scheduling Robocopy

Robocopy has a few ways you can schedule when it runs.

Using /RH

Using the /RH option, you can tell robocopy to only run during a specific time. This is great if you have a maintenance window or a time when everyone has gone home for the day.

You can specify a start time and an end time in the format HHMM-HHMM. For example, to invoke robocopy but only allow it to run between the hours of 5PM and 9AM as defined by the system clock, run:

> robocopy C:\src C:\dst /RH:1700-0900

You’ll see that if you invoke robocopy outside of those hours, it will tell you the current time and wait for the start time to run.

You must ensure that both times are in a 24-hour format and are exactly four digits long. The window must be greater than two minutes.

By default, using /RH will check for the start time before the entire run. However, if you have a lots of files and believe the process may go longer than that, you can use the /PF option. /PF will force robocopy to check the window before every file.

Using the Task Scheduler

The Output Log

Robocopy will always return an output log. Whether that log is displayed via stdout on the console and/or redirected to a log file is up to you.

You’ve got lots of options when displaying robocopy output.

Limiting Log Elements with /NJS and /NJH

By default, robocopy returns two elements in it’s output, a job header and a job summary.

The job header is the simple ROBOCOPY header at the top.

The job summary shows a summary status of all files/folders, how much data was transferred and the time the run ended.

You can hide each of these elements using the /NJH option to hide the job header and the /NJS option to hide the job summary. You can include either of these options or both of them together.

Redirecting Output Log to a File

If you need to save the output log, you can redirect it to a text file and/or display it on the console. You can do so using traditional output redirectors like >, >>, PowerShell or the /LOG option.

To redirect the output log to a file using the /LOG option overwriting any existing log file use the syntax /LOG:<filepath> like below. The only output you will receive on the console is the path to the log file.

> robocopy C:\src C:\dst /LOG:c:\file.log

 Log File : c:\file.log

If you’d like to keep the contents of any existing log file and append results to a file, you can use the + operator as shown below.

> robocopy C:\src C:\dst /LOG+:c:\file.log

 Log File : c:\file.log

Redirecting Output Log to a File and Displaying on the Console

If you’d like to save the output log to a file yet also see it on the console, you can use the /TEE option. This option causes robocopy to write the output to the log file while still maintaining the default behavior of returning output to the console.

robocopy C:\src C:\dst /LOG+:c:\file.log /TEE

Exit Codes

Like all other command-line utilities, robocopy returns exit codes depending on the results of the execution. We all wish for robocopy to always exit successfully with a 0 but that doesn’t always happen.

Below you will find all of the exit code that robocopy returns and their explanation. Any exit code greater than seven indicates at least one failure during execution.

Note that if you’re executing robocopy in a third-party utility, that utility may think any non-zero exit code is a failure. To prevent this, you can change the exit code to 0 if it returns 1.

The Robocopy “extra” file exit code is a common return code meaning an “extra” file is in the destination folder but not the source folder. This code excludes extras that will prevent any deletions from the destination.

Changing the Exit Code in a Batch File

If you’re executing robocopy with a batch file, you can find the value of the %ERRORLEVEL% variable. If it returns 1 then use the exit keyword to exit the script with 0.

> (robocopy <options>) ^& IF %ERRORLEVEL% LEQ 1 exit 0

Changing the Exit Code in a PowerShell script

If you’re executing robocopy in a PowerShell script, you can invoke robocopy with Start-Process using PassThru to return the process created and Wait to wait for robocopy to finish. You can then check the ExitCode property for a value of 1. If the exit code is 1 then exit the PowerShell script with a 0 using $host.SetShouldExit().

$exitCode = (Start-Process -FilePath 'robocopy' -ArgumentList '<option>' -PassThru -Wait).ExitCode
if ($exitCode -eq 1) {
    $host.SetShouldExit(0)
}

Common Errors

If you’re dealing with thousands of files, you’re bound to run across some problems. Here’s a breakdown of common errors I’ve come across

Error Invalid Parameter

When you see an error stating error invalid parameter, this normally means that you’ve tried to pass options to robocopy out of sequence somehow. The robocopy invalid parameter 3 error is the most common, it seems.

A common reason you’d receive this error is when you specify a source or destination directory with spaces and forget to surround it with quotes.

Robocopy Examples

You can build your own strings of robocopy or you can take what others have learned and use them! In this section, I’ll cover use cases on how to use robocopy to accomplish various things.

Find the directory size of a network folder

Contributor: northendtroooper (Reddit)

> robocopy "\\MACHINE\fileshare" c:\dummy /l /xj /e /nfl /ndl /njh /r:0 /mt:64

Quickly delete folder contents (ignoring permissions on subfolders)

Contributor: pizzasteveo (Reddit)

> robocopy c:\dummy c:\foldertodelete /MIR

Performing large file migrations

Contributor: @MySnozzberries (Twitter)

The goal of this snippet is to force ownership on all files back to Administrators. We then add an explicit ACE for the Administrators group for full control on every object recursively even though we are also setting inheritance.

Finally, we do a full robocopy copy with DACLs to the destination with log. Log can then be reviewed for additional permission issues or just file locks and another delta sync can be performed later.

> takeown /F .\test /R /A /D Y
> icacls .\test /grant "Administrators":(OI)(CI)F /T
> robocopy .\test .\test2 /E /SEC /FP /V /LOG:.\temp.log

Recursively force Administrators group as the owner of all files and directories. There can be ways around this, but this is the most heavy handed approach and usually the fastest.

> takeown /F .\test /R /A /D Y

Once we are the owner we can now force a new ACE into the DACL for every object. This grants Administrators full control with inheritance enabled and recursively through the path.

Setting this at the root with inheritance would cover the environment, but when a share has CREATOR OWNER with Full Control (which sadly is even Microsoft’s recommendation for things like file user profile stores), the user can disable inheritance or remove ACEs at their discretion. So a heavy hand is usually the fastest fix.

> icacls .\test /grant "Administrators":(OI)(CI)F /T

Once we have changed the DACLs on the majority of files we try copying the files to a new location, common for things like file share migrations. For this, we are copying the items recursively and using the /SEC switch to also copy the Data/Attributes/Timestamps/DACLs.

Then we log the operation with full paths and for all objects (/V verbose switch) to a log, so we can remediate the <5% of errors that are commonly path length or file lock related and get more granular.

> robocopy .\test .\test2 /E /SEC /FP /V /LOG:.\temp.log

This is a simple framework for managing a file share migration with minimal impact to user experience. It also improves the control IT holds over the data. If a customer has a strong data governance practice where ownership is properly managed at a child folder level, this becomes a more complicated discussion, but most customers we find are lucky to be using inheritance and group-based ACEs only, so this is the most common situation and fix we start at.

Robocopy Alternatives

Robocopy is an awesome tool but there are so many other tools similar to it that may be of interest.

• xxcopy – A similar command-line utility with tons of options.
• Copy-Item PowerShell cmdlet – Not nearly as featured but much simpler.
• TreeSize – GUI and scriptable utility to find folder information.

Summary

Robocopy is an excellent tool to copy large sets of files. Whether you’re doing a data migration, keeping folders in sync or simply need a quick way to accurately copy files, robocopy is a great choice.