Re-registering orphaned virtual machines
The virtual machine is no longer registered on the host it is associated with. That state can be caused by deleting a virtual machine directly on a host.
There are so many issues we seen while the Virtual machine becomes “Grayed Out” and inaccessible through vCenter or any other way .
1. First of all select the Orphaned VM and find the Datastore & the folder of the virtual machine where it resides. In my example its “Datastore1”
2. Now go to the specified datastore by selecting the configuration> Storage option on vcenter server or ESX (in case of stand alone host) .
3. “Right Click ” on the residing datastore and click on “Browse Datastore”.
4. Go to the specified folder of orphaned virtual machine . And select the file which extension name will be “.vmx” followed by the virtual machine name and select “right click > “Add to Inventory”.
5. After Selection it, It will open “Add to Inventory” wizard . Now provide the Name of the original virtual machine, Vcenter name, ESXi Host details, Resource pool, and it will finish the wizard with the summary details.
6 . Now you can verify all the details and check the virtual machine ..