These instructions describe how to add extra OS to a computer with a Win8 OS installed in UEFI mode. You could add an extra (small) Win8 for testing purposes or you could add a different OS such as Linux or Win10. The software used is Image for Linux and BootIt Bare Metal. Boot into IFL (uefi mode) Create a backup image of the EFI system partition. Call it oldesp.tbi Partition Work Delete the EFI system partition Create File System 239/EFh: EFI System partition in the Free Space just created by deleting the EFI system partition. Name it EFI Select the Recovery partition, Properties, change the Type to Linux Data. This prevents the impending OS install from using this partition Select the Win8 partition, Properties, change the Type to Linux Data. This hides the current Win8 from the impending OS Create a 300 MB, NTFS partition named Recovery in the free space below Win8 Select this Recovery partition, Properties, change the Type to Microsoft Recovery Create a 30000 MB, (or your choice of size) NTFS partition named Win8new in the free space below the new Recovery partition Restart into the Win8 boot disk (uefi mode) Do a Custom Install into the Win8new partition. Ignore the Setup message about partition order The new Win8 will boot Make any changes you feel necessary Boot into IFL (uefi mode) Create a backup image of the EFI system partition. Call it newesp.tbi Partition Work Select the old Recovery partition, Properties, change the Type to Microsoft Recovery Restart into new Win8 (again) To boot into old Win8, boot into IFL (uefi mode) Restore oldesp.tbi to the EFI system partition Partition Work Select the old Win8 partition, Properties, change the Type to Normal Data Select the new Win8 partition, Properties, change the Type to Linux Data Restart into old Win8 To boot into new Win8, boot into IFL (uefi mode) Restore newesp.tbi to the EFI system partition Partition Work Select the old Win8 partition, Properties, change the Type to Linux Data Select the new Win8 partition, Properties, change the Type to Normal Data Restart into new Win8