The most recent Windows Server 2016 Technical Preview iso is so large that only some DVDs readers can read it. Example try loading it on a Dell PowerEdge server. The iso was greater than 4.7GB and therefore was not burnable on the single layer DVDs we had. Simply copying the iso to a USB thumb drive will error when trying to boot because it is not a bootable device it is missing the boot loader so you will get the error message that boot file or bootmgr is missing. Note: to boot from USB on a Dell PowerEdge Server you much change settings in Dell bios to boot from USB. To work around this issue and properly boot a Windows Server Iso Image from a USB drive, we followed these steps for a windows machine:
- Have the .iso image on your local desktop/laptop or on a readable DVD.
- Download this Microsoft tool, “Windows USB/DVD Download Tool” (http://www.microsoft.com/en-us/download/windows-usb-dvd-download-tool), to your local desktop/laptop. We used this tool on a Windows 7 machine. We have seen posts where users says it works on a Windows 8 PC but have not verified it.
- Open the tool and follow prompts to copy the iso image from local machine to USB thumb driveInsert thumb drive in server and change bios boot options to boot from USB.