Windows always boots to active partition on MBR style disks!Ģ. (Right-Click drive H: and select 'Mark Partition as active') In Disk Management mark drive/partition H: as active. We suggest using Dual-boot Repair tool (which can run on Windows XP to Windows 10) for this procedure.ġ. Separating boot files and OS files on different partitions is done for protection of critical boot files - in this case the boot partition is usually hidden so boot files cannot be altered easily. There is no problem if we have only one single primary (and active) partition on disk which should be large enough to hold boot related files and also all OS and program files. OS partitions can be either primary or logical. On a MBR disk only the active (and primary) partition can be made bootable! So we need at least one active primary partition on disk were boot files will reside. It is recommended that the destination partition is formatted as NTFS (could be FAT32 on USB flash drive so USB is bootable on BIOS or UEFI firmware). Let's assume the destination drive/partition is mapped to drive H. Using FAT32 format allows booting flash drive on UEFI and on BIOS firmware! To make a bootable USB flash drive (MBR style layout) we need only one single FAT32 partition which holds boot files and OS files. Suggested layout of GPT partitions for UEFI based PCs is: Many UEFI boot problems can be solved by assuring that ESP and MS Reserved partitions are present on disk! MS Reserved partition(MSR), special Microsoft partition which is exactly 128 MB in size, no formatting.(Beginning in Windows 10, the size of the MSR is 16 MB.) On GPT style disks boot sectors are not used during Windows boot process instead two separate special partitions are needed:ĮFI System Partition(ESP) which holds boot related files (partition size 100-500 MB, formatted as FAT/FAT32). How to move Windows 7 boot files to another drive/partition and make it bootable (procedure can be used also to make a bootable USB flash drive)

Windows 7 boot drive