Hi all, I used Acronis True Image in the past with good success. However, recently it would often hang or crash altogether - for example, when I clicked "backup", it would display a progress bar and the message "Analyzing Partition C:", but it would simply hang there and never complete. This was under Windows XP, but it may also apply to other windows versions. The issue seemed to be that I had multiple physical hard disk drives, and one of those was an exact clone of the other. This means that these two HDDs also have the exact same volume ID bytes in the MBR. Since Windows uses these volume ID bytes to assign drive letters etc., bad stuff can happen if you hook up the original HDD and its exact clone to a windows machine at the same time. For example, if you boot up Windows with two such HDDs attached (one original, one clone), then Windows may boot with its left leg on the original HDD, and with the right leg on the clone HDD, figuratively speaking. Once such a thing has happened, neither HDD might be able to boot on its own, since drive letters are now cross-assigned. The typical Windows failure mode after such a SNAFU is that you get the login window, but when you log in, you are immediately logged out again. Even in safe mode. In a less severe case of volume ID conflicts, other applications such as Acronis True Image may hang or crash. The solution in all of these cases is to alter the volume ID of one HDD, so that no two logical drives share the same volume ID. Note that I am talking about the volume ID, not about the volume name. You can most easily see the volume ID by opening a command prompt window and saying DIR C: /p. You'll see something like: C:\>Dir C: /p Volume in drive C is Dell_WindowsXP Volume Serial Number is 44B3-F7FF There. I highlighted the volume ID in red. In the DOS prompt it is apparently called "Volume Serial Number". It is also know as DiskID "Disk ID", "NT serial number", or "Partition Signature". More details about it here. Anyways, if any two drives in your PC have the same volume ID, then you're likely to have problems, ranging from Acronis hangs to Windows boot failures. The solution is to alter the volume ID of either the original or the clone HDD to a different value. If you still have Windows access, this can be done with a small Microsoft Sysinternals utility from Mark Russinovich called volumeid.exe. Open a command window and use the utility and use this to create new volume IDs. Windows may hang momentarily, but after the next reboot it will re-assign its drive letters from scratch, eliminating all conflicts. If you don't have windows access, boot with a Windows 98 or Windows ME floppy disk and type at the command prompt FDISK /mbr This re-writes the Master Boot Record, but it also happens to overwrite the volume ID, as initially discovered by Michal Kawecki. Same effect, except you can't choose the volume ID freely - instead, you get a default value. So you may not want to use this method on more than one drive, otherwise you end up with duplicate volume IDs again. Anyways, I cloned my drive and had lots of problems until I changed the diskid of both drives (just to be safe) with volumeid.exe. Now everything works just fine again, including Acronis True Image. Moral of the story: Changing the volume IDs is like a rejuvenating fix for Windows, because it resets its current drive letter assignments and starts from scratch, thereby eliminating all troublesome drive letter and volume ID conflicts and ambiguities. I hope this helps someone else as well. ~ S.