How to identify orphaned MCS catalog base disks in VMWare ESX. For various reasons it might be necessary to identify which base disks are still in use by machines in a given Machine Creation Services (MCS) catalog.  The following steps will help to identify these disks. 

Instructions

There are two options to do this:

Option 1

Follow https://support.citrix.com/article/CTX272453

Option 2

First, check if there are any VMs that are pending an image update. 

1. Open PowerShell (run as admin) on any DDC

2. Load the Citrix snap-ins: asnp citrix*

3. Run the command: Get-BrokerMachine -ImageOutOfDate $true | select MachineName 

4. Reboot the listed VMs from Citrix Studio

5. After the VMs are back up from the reboot re-run the same command: Get-BrokerMachine -ImageOutOfDate $true | select MachineName (The resulting output returns nothing so all VMs are up to date)
   
   

1. Browse the VMWare data store where the VMs are located.

2. ​Here we see two base disks for the same catalog and need to determine which can be deleted​​

3. Power off one of the VMs in the catalog and browse to its folder
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4. Export the *-xd-delta.vmdk file to you local machine

5. The export will generate 2 files
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6. Open the *-xd-delta.vmdk with a text editor

7. You will see parentFileNameHint=(Location of the base disk in use by the catalog) as shown in below screenshot. Since this base disk is in use, do not delete this.
   
   
   

The other orphaned base disks that were listed in step 2 can now be safely deleted.