Templates can become unregistered from the vCenter Server if they are removed from the inventory or if the hosts with which they are associated are removed from the vCenter Server and then readded.
You must be connected to a vCenter Server system with the vSphere Client.
- From the Home page, click Datastores and Datastore Clusters.
- Right-click the datastore that contains the template and select Browse Datastore.
- Browse through the datastore folders to find the .vmtx file.
- Right-click the .vmtx file and select Add to Inventory.
The Add to Inventory wizard appears.
- Enter a template machine name, select a location, and click Next.
If you want the template to retain its original name, do not enter a name in the Add to Inventory wizard. vCenter Server will use the original name if the field in the wizard is left blank.
- Select a host or cluster on which to store the template, and click Next.
- Review your selections, and click Finish.
The template is registered to the host. You can view the template from the host’s Virtual Machine tab.