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Default Reinstall: What customers are asking

(Last updated on February 5, 2021)

What data is saved with a default reinstall?

A question that customers often ask is what data is saved with a default reinstall?  The profile data is my usual answer.  Then I had a debate with my colleague Johan who proved me wrong (as he usually does).  So, I did some more digging with the help of our R&D team.

First, a little background.  How does Deploy save data?  Deploy uses Microsoft’s free tool USMT – the User State Migration Tool.  USMT 4.0 includes a few command line utilities that back up user data to a local data store on your client machine, and another tool that restores the data after your OS is reinstalled.  Deploy uses the default templates in USMT to migrate the data, including:

  • Address Book
  • Desktop Wallpaper
  • Favorites
  • Folder Options
  • Fonts
  • Group Membership
  • Internet Explorer Settings
  • Network Drive Mappings
  • Network Printer Mappings

It also includes migrations settings for over 30 applications and many known file types including .csv, .dif, .doc*, .dot*, .mdb*,.pps*, .ppt*, .pre, .pst, .pub,.txt,.wpd, .wps, .xls – a full list can be found here: https://technet.microsoft.com/en-us/library/dd560792(v=ws.10).aspx

Where is the data stored?

The next question, where is the data stored?  is it migrated to my Deploy server? It actually never leaves the client machine.  The data is migrated to a temporary local store, and once the operating system reinstallation is complete, the data is restored back to the original location.  This is optimal if you want to save on storage costs and network performance.  You can use custom MDT settings, if there is not enough storage on the local machine and you would prefer another location, or your server. This can be done in two ways:

The first way is manually editing the customsettings.ini file located on your DeploymentRepository\Control folder.  All you need to do is change the UserDataLocation from Auto to Network and then change the UDShare name to the location where you want the data backed up and UDDir to the folder for the backup.


After you edit the file (make a backup first before you edit it), publish your deployment repository.

The second way and better option (in my opinion) is to use the Custom MDT Settings in your OS Deploy GPO.  In the last tab in your GPO, you can set the UserDataLocation to Network, and by default, it will go to your deployment server. You do not need to publish your deployment repository when you follow this method.


What happens if it fails during the backup?

What happens if it fails during the backup?  Will my data get lost?  Nothing actually happens – the installation will get aborted.  If it fails during the restore you can keep running it until it succeeds.

Here are two links that I used as references for this post and you may find the detailed information useful:



I hope this took some of the mystery out of what happens.  Happy Deployments!


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