When you convert a template back to a virtual machine and try and edit the settings you may get an error message like this one:
Call "PropertyCollector.RetrieveContents" for object "propertyCollector" on vCenter Server "vcenter.mydomain.com" failed
To fix just shutdown the VM, remove the VM from the inventory and re-add it.
1. Shutdown the VM
2. Right click the VM in the vCenter client -> Remove from inventory
3. Go to Inventory -> Datastores -> Browse the datastore which the vmdk/vmx files for the VM are on
4. Double click the VM’s folder -> Right click the vmx file -> Add to inventory
Now if you try and edit it again you’ll find it works OK.