Differential Backup not differential but always full

Hi All,

I have successfully used the Comodo Backup GUI for a year from a Windows7 desktop. I currently have version 3.0.171317.130. From this desktop, I backup Network Attached Storage (NAS) 1 to NAS 2. Both NAS 1 and 2 are mapped drives on my Window7 desktop. Until now, I was performing full backups every few weeks, but the backup took 2 days for 600GB of photos, video, music. I would like to begin using differential backups and they do not seem to be working.

I specify a new differential backup job that uses my prior full backup job via the “Differential Backup:Choose Existing Backup:From Computer” Step 1 GUI. Upon selecting the full backup on NAS 1 the correct Backup Sources appear. For step 2, I specify a save location for the differential backup that is the same folder where the full backup is stored on NAS 2, using the “My Computer” radio button and selecting the Mapped NAS 2 Drive. In Step 3, I specify a date macro and weekly schedule for the differential job. Upon execution, the Differential job says it is creating a full backup, and I am looking for it to create a differential backup. Your help with how I go about ensuring I see a differential backup would be much appreciated.


Create a new backup job :
In backup step 1 - select what to backup, choose differential with “Make new backup”
In backup step 2 - choose destination
In backup step 3 - add date & time macros
Click on schedule icon to set a schedule

On first run the backup will run as full, then next runs will be differentials. First backup will be used as base automatically.
The problem you encountered will be fixed in next release.


Thanks you for your response, Sir! Until the update comes out, I will use the setup as you have outlined.

Hi Mr Sescu,

I tried this recommendation and setup a differential backup. The first backup, a full backup, was created successfully. The next scheduled backup, a week later gave me an error, Error 46. Would you know why I got this error?

Best Regards

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An observation that may (or may not) be relevant: When I go to edit the Comodo differntial backup definition, in step 1, I no longer see the source drive nor the destination drive as options to select. The source as well as destination drives are mapped network drives. The drives do, however, show up fine in Windows+7 and I can get to them and their contents successfully.

I do recall that the way I got these drives to show in commodo to begin with, was to go to Settings and choose each drive (one drive after the other) as a “default backup location.”

If you have UAC on and J: drive is a network drive, than you must remap the network drive(s) in administrator context.
Please run cmd.exe as administrator and use “net use” command to remap them, this will make them visible in CB.