Checking Differential Archives

According to the User Manual for TI9:

"To check data from a differential backup, you must have the initial full backup as well. However, if you created several differential or both incremental and differential backups based on the same full backup (and therefore, in the same folder), you will need ALL of these successive backups to check the archive. "

I thought that the advantage of differential backups was that only the original complete backup and the latest differential backup are required to restore. I can understand why the full backup and all incremental backups would be necessary for archive checking and restoration, but why are all the successive differential backups required to check or restore the archives?

 

Hello Prizm1,

Thank you for choosing Acronis Disk Backup Software.

Please accept my apologies for the delay with the response.

Actually, your understanding is quite correct.

The point is that you have found a mistake in Acronis True Image 9.0 User's Guide.

I've forwarded this information to the respective person and so the text of Acronis True Image 9.0 User's Guide will be changed in the appropriate way as soon as possible. Your collaboration on this matter is very much appreciated.

If you have any further questions please feel free to ask.

Thank you.
--
Alexey Popov

 

What about the archive checking feature? I have read from other forum posts that you cannot delete the intermediate differential backups in between the full backup archive and the latest differential backup without the check archive feature reporting an archive error? Is this true? Let's say that I have a complete archive backup named "Complete". I also have four differential backups based on this "Complete" archive named as follows: Complete1, Complete2, Complete3 and Complete4. To do a full system recovery, I need only the Complete and Complete4 files, so I could delete Complete1, Complete2 and Complete3 and still be able to do a full system restoration with Complete and Complete4? According to others posting in this forum, I can restore my system with only the Complete and Complete4 files, but *cannot* do an archive check on Complete and Complete4 without there existing the intermediary files of Complete1, Complete2 and Complete3. Is this correct?

 

Please allow me to ask a follow up question with yours.

Why, with a differential backup would TI not write over the previous differential, if any--i.e. only keep original and one and only one differential?

I thought the advantage of differential was:

1. Faster restore. AND
2. Less space used for the backup as compared to incremental.

We need clarification on these and the previous points--please.

Thanks,

Bill

 

Are you sure you would want TI to automatically overwrite your only differential? What if something had gone wrong with your system (virus, bad software install etc) after the last differential and you needed to restore back to that point but before you realized the problem, TI had zapped it with a later differential? I would prefer to be able to manually delete old differentials only when I'm sure I won't need them again.