Try disconnecting any drives that don’t contain an operating system. In this tutorial you can find detailed instructions on how to resolve the '' An operating system wasn’t found. from Windows 8.1 to Windows 10), a BIOS update, or after you have cloned your hard drive to another disk.
The ' An operating system wasn’t found' error can be displayed on Windows 10 or Windows 8.1 computers, after a Windows upgrade (e.g. The following error may appeared on Windows 10 or 8.1 computer during boot process ' An operating system wasn’t found.
