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Disk backup size difference - disk mode vs partition mode

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I have Win7 x64, using ATIH 2011 with Plus Pack. I have made a disk backup of my drive where I specify to backup all partitions in the partition mode view and then I did another disk backup where I specify to backup the drive in the drive mode view. The disk backup in drive mode is 13.58GB and the disk backup in partition mode is 12.95 GB. Why is there a 0.63 GB (4.9%) size difference between the two backups?

If you look at the Disk Recovery window in both backups you get the same recovery options - if you switch to disk mode view you can recover the entire drive and if you switch to partition mode view you have a choice of recovering any combination of the MBR, the 100 MB Win7 system reserved partition, and the local disk partition. Both backups let you alternate between the disk mode view and the partition mode view.

So, it is not clear why there is a size difference between the two backups. The backups were made back to back so the drive had the same files/folders. Also, the same settings were used for both backups, just one specified what to backup in the disk mode view and the other specified what to backup in the partition mode view.

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What build are you using?

You don't have NSB running or any program that might have updated itself in the interim?

Does the PC have a hidden diagnostics or OEM partition?

Pagefile still the same size? Note this is only a placeholder in a TIH image not an actual folder.

I think only one of them has the MBR and Disk Signature.

My guess is that you backed up first in the partition mode and then Windows may have created a restore point before your next backup in the disk mode. Restore points can be triggered by installation of software, Windows Updates, or Antivirus definition updates. Any chance one of these may have occurred between the two backups?

If you're up for an experiment, do the two different kinds of backups from the boot CD while Windows is shut down. Both backups SHOULD be the same size.

Here are answers to the questions up to now.

  1. I am using build 6696, the latest one.
  2. Right now, I am not using NSB, just differential backup.  It is not scheduled.  I searched on files updated 2/27 and checked for the 2.5 hours between backups.  I only see several MB of files updated during that time; I wasn't using the PC during that time.  Also, only 2 folders updated during that time, one is 0 bytes and the other had less than 1MB (both Acronis folders).
  3. I built the PC myself, no OEM or hidden partition. Only the 2 partitions mentioned above.
  4. I don't know the pagefile size before and after; it is set to system managed so it may have changed in size. However, my understanding is that the pagefile is not backed up so I don't believe it will make a difference in the backup size (I think you're saying the same thing since you mention it is only a placeholder.)
  5. I checked and both backups offer to restore disk signature and MBR.
  6. All restore points are date/time stamped prior to the first backup.

I'll try the experiment of doing both backups from boot CD.