How to: Link a Rebuilt PC to its Old Windows Home Server Backups

Here is another Home Server How To coming from a post at WGS Forums. This one is not for the beginner, as it involves some delving around in the Registry, putting your machine at risk if you slip up. It’s taken a while to bring together from two or three threads in the forums but the process has been refined as a result.

Imagine this scenario: One of your PCs has had a hard disk failure, or you are rebuilding the PC for some other reason – like an OS upgrade. Once done, you install the Windows Home Server Connector and even though you have given the PC exactly the same name (or maybe you didn’t) you see the computer listed as a new PC in the WHS Console. You would really like your newly rebuilt system to be associated with the backups of the same system you have from before, but you cannot see any way to achieve this. This becomes particularly relevant for those moving from XP to Windows 7 as you have no way to preserve the settings from your old PC. Suddenly, you end up with an extra PC in your WHS list and you are not sure why, or what to do with the old one. Today, we’ll help you reunite your rebuilt PC with its former backups on Windows Home Server.

But first, let us delve into why this looks like a new PC to Windows Home Server. When the Connector is first installed on a PC, it creates a number of keys in the registry. These cover your backup preferences, which server the is associated with, the PC’s name and most importantly a unique GUID (Globally Unique Identifier). This is one of those long strings of alphanumerics enclosed in curly brackets that you see so often in Windows. To WHS, the GUID is all important, more so than the PC’s name. Names may change, but if the GUID remains the same, it is the same entity. Here lies the problem. A new build with a fresh OS install has a registry void of WHS settings and the all important GUID. Install the Connector and a new, unique GUID is created and so you have a new system connected to Windows Home Server.

Those of you half a step ahead of me will have worked out that a bit of forward planning would help the user here. Export the GUID Registry key before rebuilding and then bring it into the new build and WHS will still see it as the original PC and keep it linked to the old backups. To do this, follow these steps CAREFULLY (Regedit Alert).

1. On the PC about to be rebuilt, run Regedit. On Windows 7 and Vista, just type in regedit into the Start Menu’s search bar, and it should pop up


2. Navigate to Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Home Server


3. Right-click on the words ‘Windows Home Server’ in the tree in the left-hand pane of Regedit and select Export


4. In the dialog box that pops up, navigate to somewhere where you will be able to find the file and save as WHS.reg


5. Exit Regedit. Save the WHS.reg file somewhere safe – USB key, external drive on on the server – so you can get at it after you have rebuilt the PC.

6. You can now rebuild your server with whichever version of Windows you like.

7. Once installed and set up, but before installing the WHS Connector, copy the WHS.reg file to somewhere where the PC can access it and double-click it. This will import the settings into the PC’s registry.

8. Now install the Windows Home Server Connector and your server will identify it as the original PC making a new appearance.

This is fine for those who have the benefit of acting in advance, but what do you do if your hard drive or your memory (the one in your head) failed and you haven’t got access to that original registry?

Try the following procedure as it may well help. I would add at this point is has not been exhaustively tested and so feedback would be welcome.

1.  We need to run Regedit on the server itself. The warnings above now should be heeded with even more care. Mess this up and you won’t have a backup to help you. You can either run Regedit by creating a Remote Desktop Connection to the server (Start> All Programs > Accessories > Remote Desktop Connection) and running from the Start menu (Select Start > Run and type in regedit to open).


Or you can use the more convenient method of using the  Advanced Admin Console add-in (you are all using this excellent add-in, aren’t you), where you will find it in the drop-down menu on the far right of the window.




  1. So I take it that this only works when you do it during the initial install of the Connector software… Are those of us that had this happen some time ago and need to keep backups on both the old and new computer installations (with the same name) out of luck? Any way to migrate the backups of the old and new installation together?

    1. Unfortunately, there is no way (currently known) to merge backups once they have occurred. If you only wanted to keep one of the old backups, you could restore it to a USB drive and then back that up as part of a PC backup. Once done, you could then remove the old PC entry.

      1. Great Article, and great suggestion!!
        I recently ran into this after upgrading one of my laptops. At least for the future I know how to prevent it – I will keep a restored backup on a USB drive as you suggest so I can later use it if needed; this will allow me to get rid of the "old PC defintion" on WHS.

  2. This is an excellent article! Thanks to Dave and all the people involved in figuring this out as I'm sure it will be helpful to a number of people. Now if only we can get this kind of integration into Vail.

  3. I'm getting ready to upgrade from xp to Win7 so this is great information. Only one question. You say, "…copy the WHS.reg file to somewhere where the PC can access it and double-click it."

    So can I just put the file on the desktop? The export creates an executable file that automatically inserts it into the registry?

    1. Copying it back to the PC desktop is fine. If you have it on a USB Stick, you can double-click on it there to get the reg key information back into the registry. Windows assumes a file with a .reg suffix is a set of registry keys.

  4. If there are several machines on the WHS network saving the key for each machine Thumb drive or CD would help from a disaster recovery. The original SID could be restored.

      1. Hi Dave, how exactly does one get the GUID from a backup? I had a motherboard AND hard drive die (lightning! curse you!) and now want to put my backup onto a new mb/hd combo after the fact. I can open the backup in whs and see the volume on another home pc – now what? Thanks so much for any help you can offer!

  5. This is great. I used the procedure to retrieve the GUID from the server because the old computer crahsed. No need to say they are totally different with different hard drives. Here is are a few additional steps to get over the HDD problem. Do this after the new computer is connected to the old profile.
    – In de WHS Console on the "Computers & Backup" tab, right click on the computer you are rebuilding and choose "Configure Backup".
    – Click "Next" in the Backup Configuration Wizard.
    – In the "Choose Volumes to Back Up" screen, disable the "Unknown/Not Connected" drives, these are the drives of the old computer.
    – Click Next » Next
    – In the "Confirm Configuration of Backup" screen, choose "Save them on the server", to keep the backups from the old computer.
    – Click Next » Done

  6. This is likely going to be very helpful when I upgrade my client from xp to w7. Please excuse my newbie understanding of this upgrade process, but I'm wondering about whether upgrading from xp 32-bit to w7 64-bit will have any consequences in restoring my c-drive from whs backups – since I will have to do a fresh install on my c-drive (I believe that my d-drive will remain untouched through the upgrade). Your advice would be much appreciated.

  7. @Carl, you can't do a full restore of your XP backup, that will bring the machine back in the exact same state as how it was during the backup, including the Windows operating system, all your software, settings and files. If you want to do a fresh w7 install, you should just open the backup and copy your files (ie my documents etc) over from the backup to the freshly installed w7. If it is on the same computer, you may want to find out first where all files are located (favorites, email, program settings…). You can also use "Windows easy transfer", see

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