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Differential backup does not restart set number after a full restore

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Hi... some weeks ago I had a trouble on my desktop and so I decided to do a restore of the full machine from last backup I had.

After this action I noticed that all following differential backups where so big, like the first set backup, maybe because all data restored are considered "a difference" from the first backup file.

That's ok. But at the end of the set, I expected that a new backup set were done, but not, the incremental counter is going beyond the max number configured.

In other words... I have a backup set configuered for a new backup after 8 differential backups. Last set is named XXXX_diff_b6_sYYY.tib. After the _b6_s3 backup I made the full restore. I expected a new backup set after last differential backup named _b6_s8  (as usual) but now the counter has reached the _b6_s11 ... Why a new backup set does not start yet? This is filling my destination backup...

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fabryd, you have introduced several different albeit related issues in your post above.

One of the issues of doing a full restore is that you are also restoring all the files which store information about your backup tasks and their history of backups, thus you are resetting these values back to the state they were in when the restored backup was created, and this overwrites any data you may have had for any later backups you have created since that backup was made.

Now, when you run your backup task, I would expect that any new backup, but especially any differential or incremental backups will be significantly larger than if you had not restored.  Acronis determines changed data based on changes to data at a sector level and the restore has effectively touched / changed a whole lot of sectors on the drive.

The best advice I can offer for following a full restore would be to start off a brand new backup task and remove the settings for the previous task (keeping the backup files for protection against needing to restore anything else).  This is because the Acronis Database now has information about the previous backup task that no longer matches the actual backup files found on your storage drive, this in turn may result in resetting the chain counter so that instead of a new full backup being created after 8 differentials, this will now happen after the 11th backup (S3 + 8).

Hi Steve... The mean of the differential backup big size was clear, but I couldn't realize why a new set wasn't started yet. Well... I understand that next scheduled backup will be a new set backup, since the last was the 11th.

Thanks for your explanation.