Acronis Backup for Windows Server Essentials - User Guide - Manual (Page 140)

140 Copyright © Acronis International GmbH, 2002-2014
The software will keep the NT signature of the target disk if it is the same as the NT signature
stored in the backup. (In other words, if you recover the disk to the same disk that was backed
up.) Otherwise, the software will generate a new NT signature for the target disk.
This is the default selection recommended in most cases. Use the following settings only if you
absolutely need to.

Create new
Acronis Backup will generate a new NT signature for the target hard disk.

Recover from backup
Acronis Backup will replace the NT signature of the target hard disk with one from the disk
backup.
Note: You should be absolutely sure that none of the existing disks on this machine has the same NT
signature. Otherwise, the operating system runs from the first disk at the startup; discovers the same
signature on the second one, automatically generates a new unique NT signature and assigns it to the
second disk. As a result, all the volumes on the second disk will lose their letters, all paths will be invalid on
the disk, and programs won't find their files. The operating system on that disk will be unbootable.
Recovering the disk signature may be desirable due to the following reasons:

Acronis Backup schedules tasks using the signature of the source hard disk. If you recover the
same disk signature, you don't need to re-create or edit the tasks created previously.

Some installed applications use disk signature for licensing and other purposes.

This enables you to keep all the Windows Restore Points on the recovered disk.

To recover VSS snapshots used by Windows Vista's "Previous Versions" feature.

Keep existing
The program will leave the NT signature of the target hard disk untouched.
How the automatic mapping works
Acronis Backup automatically maps the disks or volumes to the target disks only if the system
bootability can be preserved. Otherwise, the automatic mapping is canceled and you have to map
the disks or volumes manually.
Also, you have to map the volumes manually if they are Linux logical volumes, or Linux software RAID
(MD devices). For more information on recovering logical volumes and MD devices, see Recovering
MD devices and logical volumes (p. 44).
The automatic mapping is performed as follows.
1. If the disk or volume is recovered to its original location, the mapping process reproduces the
original disk/volume layout.
The original location for a disk or volume means exactly the same disk or volume that has been backed up.
A volume will not be considered original if its size, location or other physical parameters have been changed
after backup. Changing the volume letter or label does not prevent the software from recognizing the
volume.
2. If the disk or volume is recovered to a different location:

When recovering disks: The software checks the target disks for size and volumes. A target
disk must contain no volumes and its size must be large enough to place the disk being
recovered. Not initialized target disks will be initialized automatically.
If the required disks cannot be found, you have to map the disks manually.

When recovering volumes: The software checks the target disks for unallocated space.