Templates can become unregistered from vCenter Server if they are removed from the inventory or if the hosts with which they are associated are removed from vCenter Server and then readded.
- In the vSphere Client, navigate to the datastore that contains the template.
- Select the datastore and click the Files tab.
- Locate the template folder and click it to display the template files.
- Select the .vmtx file and click the Register VM icon.
The Register VM Template wizard opens.
- On the Select a name and folder page, specify a name and location for the template and click Next.
- On the Select a compute resource page, select a host or cluster on which to store the template and click Next.
- On the Ready to complete page, review your selections and click Finish.
- (Optional) To verify that the template is reregistered, check the host or cluster inventory.
Browse to the host. On the VMs tab, click VM Templates.
On the VMs tab, click VM Templates.
The template is registered to the host. You can view the template by clicking on the host's VM Templates.