Update configure-endpoints-vdi.md

Adding important note to help avoid common issue that generates support tickets and escalations to MDE engineering team.

Author: amirsc3

defender-endpoint/configure-endpoints-vdi.md

@@ -103,6 +103,10 @@ The following steps guide you through onboarding VDI devices and highlight steps
    | Single entry for each device | 1. Select the **PowerShell Scripts** tab, then select **Add** (Windows Explorer opens directly in the path where you copied the onboarding script earlier). <br/>2. Navigate to onboarding PowerShell script `Onboard-NonPersistentMachine.ps1`. There's no need to specify the other file, as it's triggered automatically. |
    | Multiple entries for each device | 1. Select the **Scripts** tab, then select **Add** (Windows Explorer opens directly in the path where you copied the onboarding script earlier). <br/>2. Navigate to the onboarding bash script `WindowsDefenderATPOnboardingScript.cmd`. |
 
+   > [!NOTE]
+   > When using the 'Single entry for each device' method for onboarding non-persistent VDI devices to Microsoft Defender for Endpoint, ensure that the Onboard-NonPersistentMachine.ps1 script is executed only after the virtual machine has received its final hostname.<br>
+   > For example, if your VDI provisioning process involves multiple reboots or configuration stages after the VM is cloned from a master image, delay the script execution until the final machine name is assigned. Running the script too early may result in duplicate device entries or onboarding failures.
+
 5. Test your solution by following these steps:
 
    1. Create a pool with one device.