Merge pull request #2603 from dkouzmanovMSFT/docs-editor/device-control-deploy-manage-g-1738249508

Include XML validation steps -- Emm is reviewing

Author: padmagit77

defender-endpoint/device-control-deploy-manage-gpo.md

@@ -1,10 +1,10 @@
 ---
 title: Deploy and manage device control in Microsoft Defender for Endpoint with Group Policy           
 description: Learn how to deploy and manage device control in Defender for Endpoint using Group Policy
-author: denisebmsft
-ms.author: deniseb
+author: emmwalshh
+ms.author: ewalsh
 manager: deniseb 
-ms.date: 01/09/2025
+ms.date: 01/31/2025
 ms.topic: overview
 ms.service: defender-endpoint
 ms.subservice: asr
@@ -43,7 +43,7 @@ If you're using Group Policy to manage Defender for Endpoint settings, you can u
 
 ## Set default enforcement
 
-You can set default access such as, `Deny` or `Allow` for all device control features, such as `RemovableMediaDevices`, `CdRomDevices`, `WpdDevices`, and `PrinterDevices`.
+You can set default access, such as `Deny` or `Allow` for all device control features including `RemovableMediaDevices`, `CdRomDevices`, `WpdDevices`, and `PrinterDevices`.
 
 :::image type="content" source="media/set-default-enforcement-deny-gp.png" alt-text="Screenshot of set default enforcement." lightbox="media/set-default-enforcement-deny-gp.png":::
 
@@ -87,12 +87,12 @@ To configure the device types that a device control policy is applied, follow th
 
    1. On a device running Windows, go to **Computer Configuration** > **Administrative Templates** > **Windows Components** > **Microsoft Defender Antivirus** > **Device Control** > **Define device control policy groups**.
 
-   2. In the **Define device control policy groups** window, specify the network share file path containing the XML groups data.
+   2. In the **Defined device control policy groups** window, specify the network share file path containing the XML groups data.
 
 You can create different group types. Here's one group example XML file for any removable storage and CD-ROM, Windows portable devices, and approved USBs group: [XML file](https://github.com/microsoft/mdatp-devicecontrol/blob/main/windows/device/Group%20Policy/Scenario%202%20GPO%20Removable%20Storage%20Group.xml)
 
 > [!NOTE]
-> Comments using XML comment notation `<!--COMMENT-->` can be used in the Rule and Group XML files, but they must be inside the first XML tag, not the first line of the XML file.
+> Comments using XML comment notation `<!--COMMENT-->` can be used in the Rule and Group XML files, but they must be inside the first XML tag, not the frontline of the XML file.
 
 ## Define Policies
 
@@ -101,7 +101,7 @@ You can create different group types. Here's one group example XML file for any
 
 1. Create one XML file for access policy rule.
 
-2. Use the properties in removable storage access policy rule(s) to create an XML for each group's removable storage access policy rule. 
+2. Use the properties in removable storage access policy rules to create an XML for each group's removable storage access policy rule. 
 
    Ensure root node of the XML is PolicyRules, for example, the following XML:
 
@@ -121,10 +121,45 @@ You can create different group types. Here's one group example XML file for any
 
    2. In the **Define device control policy rules** window, select **Enabled**, and then specify the network share file path containing the XML rules data.
 
+## Validating XML files
+
+Mpcmdrun built in functionality to validate XML files that are used for GPO deployments. This feature enables customers to detect any syntax errors the DC engine might encounter while parsing the settings. To perform this validation, administrators should copy the following PowerShell script and provide the appropriate file path for their XML files containing the Device Control rules and groups.
+
+```
+#Path to PolicyRules xml. Provide the filepath of the device control rules XML file
+$RulesXML="C:\Policies\PolicyRules.xml"
+
+#Path to Groups XML. Provide the filepath of the device control groups XML file
+$GroupsXML="C:\Policies\Groups.xml"
+
+#Retrieve the install path from Defender
+$DefenderPath=(Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Windows Defender" -Name "InstallLocation").InstallLocation
+
+#Test PolicyRules
+& $DefenderPath\mpcmdrun.exe -devicecontrol -testpolicyxml $RulesXML -rules
+
+#Test Groups
+& $DefenderPath\mpcmdrun.exe -devicecontrol -testpolicyxml $GroupsXML -groups
+```
+
+
+If there are no errors, the following output will be printed in the PowerShell console:
+
+
+```
+DC policy rules parsing succeeded
+Verifying absolute rules data against the original data
+Rules verified with success
+DC policy groups parsing succeeded
+Verifying absolute groups data against the original data
+Groups verified with success
+Has Group Dependency Loop: no
+```
+
 > [!NOTE]
 > To capture evidence of files being copied or printed, use [Endpoint DLP.](/purview/dlp-copy-matched-items-get-started?tabs=purview-portal%2Cpurview)
 > 
-> Comments using XML comment notation `<!-- COMMENT -->` can be used in the Rule and Group XML files, but they must be inside the first XML tag, not the first line of the XML file.
+> Comments using XML comment notation `<!-- COMMENT -->` can be used in the Rule and Group XML files, but they must be inside the first XML tag, not the frontline of the XML file.
 
 ## See also