Recovering disks

Let's assume you backed up a whole disk (with all its volumes) and want to recover this disk to a different target platform.

The ability of the recovered system to boot up in different modes depends on the operating systems installed on the source disk. Operating systems can be convertible i.e. allow changing the boot mode from BIOS to UEFI and back, or non-convertible. For the list of convertible operating systems, see Recovering volumes.

When a source disk contains one or more operating systems and all of them are convertible, the boot mode can be automatically changed. Depending on the current boot mode, the target disk may be initialized either to GPT or to MBR partitioning style.
If at least one operating system on a source disk is non-convertible (or the source disk contains any boot volumes of the non-convertible OSes), the boot mode cannot be changed automatically and the software will initialize the target disk as the source one. To boot up the target machine, you have to turn on/off the UEFI mode in BIOS manually. Otherwise, the system will not boot after recovery.

The following table summarizes all cases of recovering disks of a BIOS-based system to UEFI-based and vice versa.

Green background means that the system will be bootable. No user action is required.
Yellow background means that you need to perform additional steps to make the system bootable. These steps are not possible on some machines.

Original system	Target hardware

Original system	BIOS	UEFI
BIOS OS: convertible		The target disk will be initialized as GPT. The OS will be automatically converted to support UEFI booting. If you want to recover the source disk “as is”: Turn off the UEFI mode in BIOS. Boot from a bootable media, and perform the recovery.
BIOS OS: non- convertible		The target disk will be initialized as the source one (MBR). The target machine must support BIOS. Additional steps Turn off the UEFI mode in BIOS. Boot from a bootable media, and perform the recovery.
UEFI OS: convertible	The target disk will be initialized as MBR. The OS will be automatically converted to support BIOS booting. If you want to recover the source disk “as is”: Turn on the UEFI mode in BIOS. Boot from a bootable media, and perform the recovery.
UEFI OS: non- convertible	The target disk will be initialized as the source one (GPT). The target machine must support UEFI. Additional steps Turn on the UEFI mode in BIOS. Boot from a bootable media, and perform the recovery.

Recovery to large disks in BIOS

After a recovery to a BIOS-based system, the target system disk is initialized as MBR. Because of disk size limitations in BIOS, if the disk is larger than 2 TB, only the first 2 TB of disk space will be available for use. If the machine supports UEFI, you can overcome this limitation by turning on the UEFI mode and then performing the recovery. The disk is initialized as GPT. The 2-TB limitation for GPT disks does not exist.