HOWTO: In-Place Upgrade Windows 7 Pro OEM to Windows 7 Enterprise

Recently we inherited a new client with some very legacy desktops running an OEM version of Windows 7 Pro.  The bad news for us though was there were a few legacy applications installed on those old desktops that we just could not get to reinstall on the new Windows 7 Enterprise edition machines the client purchased from us, so we decided to just P2V the old desktops into the customer’s VMware cluster, and provide the end users RDP access to their old desktop until we could deploy a validated solution to replace those nontransferable legacy apps.  This worked fine for some of the end users, but some of the other end users needed multi-monitor support.  Windows 7 Pro does not support multi-monitors as a RDP host, but Windows 7 Enterprise certainly does.

The problem is though, there is no supported method by Microsoft to in-place migrate from Windows 7 Pro to Windows 7 Enterprise edition.  That said, there is a method (obviously unsupported by MS) to accomplish this without losing your data if you are brave enough to go down that road.

Before proceeding, a full machine backup is recommended (use something like Veeam Endpoint Backup to create a backup, or if it is a VM, take a snapshot).  Download and extract the most recent Volume Licensing Windows 7 Enterprise iso to the C: drive of the machine. (SW_DVD5_SA_Win_Ent_7w_SP1_64BIT_English_-2_MLF_X17-58882.ISO is the most current Windows 7 Enterprise ISO as of 2016.03.28).  And if the machine utilizes disk encryption, decrypt the volumes before continuing.

After the above items are attended to, open an Administrative Command and run:

REG ADD "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion" /f /v "EditionID" /t REG_SZ /d "Enterprise"
REG ADD "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion" /f /v "ProductName" /t REG_SZ /d "Windows 7 Enterprise"

Next (do not reboot after you make the above registry edits), from the extracted ISO run setup.exe, and when prompted for the type of installation you wish to perform, select the option to Upgrade.

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If nothing is blocking the upgrade (from a compatibility standpoint), then setup will begin an in-place upgrade and reboot the machine several times.  Once the upgrade has completed, you should find yourself with a correctly installed Windows 7 Enterprise Edition instance.

The next step is to activate Windows by installing a Windows 7 Enterprise MAK license key and activating it.  To do so, open an Administrative command prompt and run:

cscript c:\windows\system32\slmgr.vbs /ipk XXXXX-XXXXX-XXXXX-XXXXX-XXXXX
cscript c:\windows\system32\slmgr.vbs /ato

By default the in-place upgrade process “breaks” .NET 4.x, in that Windows does not recognize it is installed, and as a result, any attempt to update, reinstall, or patch any of the .NET 4.x framework will fail.  To fix this, download the current .NET Framework cleanup tool from:

Extract the cleanup tool and run it.  In the version drop-down box, select the latest version (4.6.1 as of 2016.03.28), and select “Cleanup Now”

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When the cleanup finishes, run cleanup again, and select version 4.6.  Then repeat for 4.5.2, 4.5.1, 4.5, and finally 4.

Next, download and install the prerequisites for Internet Explorer 11 from  You can safely postpone rebooting until you get all the prerequisite installed.

These prerequisite include:

After rebooting, download and install Internet Explorer 11.

Finally you should now be able run Windows Updates and re-install all 217 plus post SP1 Windows 7 updates.

And if you took a VM snapshot before beginning – don’t forget to clean it up now!

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