Recently I had to get rid of multiple vms through VRA, However, I found that some of the vms status was showing as missing. This happens if the VM has already been deleted through the vCenter and VRA can’t find that VM in the vCenter.
The way you can see the missing status is you go to the deployments tab, check the Status if its ON, OFF or Missing (?) as the screenshot shows below:
Some of the info in the screenshot has been removed to protect my Organization Data and the VM Names have also been changed for the same purpose.
In VRA 7.6, you can unregister it easily using the GUI, You click on the Deployment Name
Hope this post helps, as I was not able to see any blog posts regarding this simple unregister procedure in VRA 7.6