Hello.   This may imply that the OS Virtual Disk (VD) is not selected as a bootable device in the controller BIOS. Double check within the controller BIOS and determine which VD is selected as a bootable device. See page 59 of Users' Guide for detailed information: [URL]  
Hello, I am Facing an issue with DELL R720 Server while booting the OS. The Server is having 2 no's 300GB Harddisk Configured as RAID-1 for Windows OS.(C: Drive)-MBR and 4 No's of 1TB Harddisk Configured as RAID-5 for For Data.(D: Drive)-GPT Both the Hardisks in the C Drive got Crashed, so i have replaced it with new Hardisk and Restored the Acronis Image. I have Restored the Image only to C Drive, but after the restoring the Image the windows is not starting. it is giving the Message "No boot Device Available.Current Boot mode is Set to BIOS.Please Ensure Compatible bootable media is available.Use the System setup program to cahnge the boot mode as needed." But if i  plug Out the 4 no's of 1TB hardisk configured as RAID-5 , the windows is booting Normally without any Issue. Once OS is loaded and logged in i put back the 4 nos of  1TB harddisk, after that i imported the foregin Confgiuration using DELL Open Manage , the D Drive appeared and able to get the data. But the moment i restart the server, same issue is happening, it is not able to load the OS. Why the Wndows is not able to load while D Drives are present ?  
OS not Booting while D Drive Disk are Present-DellR720 Server