- VMware ESXi 5
- Backup with Veeam B&R 6
- Windows Server 2012 VM
Sometimes can happen that VM losts boot configuration, making impossible right startup and forcing user change manually the configuration. Windows Server 2012 use EFI bios, so the boot is totally different from the classic bios.
In order to resolve this issue, you must open the folder, on ESXi Datastore, where are located VM's files and remove the file with .nvram extension. This operation will recover boot. I'm not sure about the real reason, because I don't know if it's guilt of ESXi of Veeam.....this is the reason why I've insert the complete scenario!
Update: the cause was Veeam B&R. To resolve this issue you need to install the Patch 3. More details into KB1751 (http://www.veeam.com/KB1751)