How to discover Office and Windows KMS hosts and remove unauthorized instances - Microsoft 365 Apps (2024)

This article was written by Eric Ellis, Senior Support Escalation Engineer.

When you troubleshoot KMS configuration and activation issues, you may find unexpected Windows or Office KMS hosts in their environment. This article describes how to discover Office and Windows KMS hosts through DNS, and how to remove unauthorized KMS hosts.

Discover Office and Windows KMS hosts through DNS

By default, Windows and Office clients discover KMS hosts through DNS and a related _vlmcs SRV record. To determine whether a KMS client can locate a KMS host or whether unwanted KMS hosts exist on the network, run a command similar to the following:

nslookup -type=srv _vlmcs._tcp >%temp%\kms.txt

Review the kms.txt file, and it should contain one or more entries similar to the following:

_vlmcs._tcp.contoso.com SRV service location: priority = 0 weight = 0 port = 1688 svr hostname = kms-server.contoso.com |

Running this nslookup command frequently reveals _vlmcs SRV entries that are tied to unauthorized Windows or Office KMS hosts.

Remove unauthorized Windows KMS hosts

In many cases, Windows KMS hosts may be unintentionally set up by users who mistakenly entered a KMS host product key, instead of a Windows client product key. To resolve this issue, follow these steps on the computer(s) in question, replace the KMS product key and convert it to a KMS or MAK client:

1. Open an elevated command prompt.

2. Run cscript slmgr.vbs /ipk xxxxx-xxxxx-xxxxx-xxxxx-xxxxx, where xxxxx-xxxxx-xxxxx-xxxxx-xxxxx is Windows product key (there should be 25 numbers).

3. To prevent instability in the license service, restart the system or the Software Protection Service. To restart the Software Protection Service, run the following commands:

   net stop sppsvcnet start sppsvc

4. Run the following command to display the license information for the installed and active Windows edition:

   cscript slmgr.vbs /dli

5. In DNS Manager, locate the appropriate forward lookup zone, and then delete the _vlmcs SRV records that exist for each computer which is not to serve as a Windows KMS host.

   See Also

   What is AWS Key Management Service (AWS KMS)?

For more information, see the following articles:

• Slmgr.vbs Options
• Deploying KMS Activation

Remove unauthorized Office KMS hosts

It's not common to create an Office KMS host unintentionally, because setting up an Office KMS requires a specific product key and the installation of the Microsoft Office 2010 KMS Host License Pack.

To determine whether a computer has the Office 2010 KMS Host License Pack installed and has an active Office KMS host, run the following command:

cscript slmgr.vbs /dlv bfe7a195-4f8f-4f0b-a622-cf13c7d16864

The output of a computer which has the Office 2010 KMS Host License Pack installed resembles the following. In the following example, key items are Partial Product Key: XXXXX and License Status: Licensed. These items indicate that the Office 2010 KMS host key is successfully installed and activated. To pull all the products installed, including all Office KMS host installations, run the following command:

cscript slmgr.vbs /dlv All >C:\<path>\KMSInfo.txt

In this command, <path> equals where you want to write the output. In this file, search for Office and find all the instances for the Office KMS host installations. If you only want to pull specific Office KMS information, replace the Activation ID that is mentioned earlier in the command (bfe7a195-4f8f-4f0b-a622-cf13c7d16864) with the Activation ID for Office 2013, 2016, or 2019. An example of the output resembles the following:

Name: Microsoft Office 2010, KMSHost editionDescription: Microsoft Office 2010 KMS, VOLUME_KMS channelActivation ID: bfe7a195-4f8f-4f0b-a622-cf13c7d16864Application ID: 59a52881-a989-479d-xxxx-xxxxxxxxxxExtended PID: Installation ID: Processor Certificate URL: https://go.microsoft.com/fwlink/p/?LinkID=88342Machine Certificate URL: https://go.microsoft.com/fwlink/p/?LinkID=88343Use License URL: https://go.microsoft.com/fwlink/p/?LinkID=88345Product Key Certificate URL: https://go.microsoft.com/fwlink/p/?LinkID=88344Partial Product Key: XXXXXLicense Status: LicensedRemaining Windows rearm count: 1Trusted time:Key Management Service is enabled on this computerCurrent count: 0Listening on Port: 1688DNS publishing enabledKMS priority: Normal

Then, follow these steps to remove an Office KMS host in your environment:

1. Open an elevated command prompt.

2. Run the following command to uninstall Office KMS host product key:

   cscript slmgr.vbs /upk bfe7a195-4f8f-4f0b-a622-cf13c7d16864

   Warning

   If the command is run without the Office activation ID (bfe7a195-4f8f-4f0b-a622-cf13c7d16864), all installed product keys are uninstalled, including those for Windows.

3. Run the following command again to check the status of the Office KMS host:

   cscript slmgr.vbs /dlv bfe7a195-4f8f-4f0b-a622-cf13c7d16864

4. If the Office KMS host product key is removed, the output resembles the following. The key items are This license is not in use and License Status: Unlicensed.

   Name: Microsoft Office 2010, KMSHost editionDescription: Microsoft Office 2010 KMS, VOLUME_KMS channelActivation ID: bfe7a195-4f8f-4f0b-a622-cf13c7d16864Application ID: 59a52881-a989-479d-xxxx-xxxxxxxxxxExtended PID: Installation ID: Processor Certificate URL: https://go.microsoft.com/fwlink/?LinkID=88342Machine Certificate URL: https://go.microsoft.com/fwlink/?LinkID=88343Use License URL: https://go.microsoft.com/fwlink/?LinkID=88345Product Key Certificate URL: https://go.microsoft.com/fwlink/?LinkID=88344This license is not in use.License Status: UnlicensedRemaining Windows rearm count: 1Trusted time: 

5. In DNS Manager, locate the appropriate forward lookup zone, and then delete the _vlmcs SRV records that exist for each computer which is not to serve as an Office KMS host.

For more information, see the following articles:

• KMS activation of Office 2013
• Troubleshoot volume activation for Office 2013
• KMS Activation of Office 2016/2019