Merge pull request #207978 from TomHickling/patch-35

Update set-up-customize-master-image.md

Author: v-regandowner

articles/virtual-desktop/set-up-customize-master-image.md

@@ -12,7 +12,7 @@ manager: femila
 This article tells you how to prepare a master virtual hard disk (VHD) image for upload to Azure, including how to create virtual machines (VMs) and install software on them. These instructions are for a Azure Virtual Desktop-specific configuration that can be used with your organization's existing processes.
 
 >[!IMPORTANT]
->We recommend you use an image from the Azure Image Gallery. However, if you do need to use a customized image, make sure you don't already have the Azure Virtual Desktop Agent installed on your VM. Using a customized image with the Azure Virtual Desktop Agent can cause problems with the image, such as blocking registration and preventing user session connections.  
+>We recommend you use an image from the Azure Image Gallery. However, if you do need to use a customized image, make sure you don't already have the Azure Virtual Desktop Agent installed on your VM. Using a customized image with the Azure Virtual Desktop Agent can cause problems with the image, such as blocking registration as the host pool registration token will have expired which will prevent user session connections.  
 
 ## Create a VM