I have a SBS2011 running Windows Server Backup every night to a 2TB disk which is formatted with NTFS and attached as a normal drive. The reason is that I'd like to be able to take offline copies of this disk and put in a safe location in case of catastrophy.

When I look at properties for the drive I see that 'Used space' is 1,24TB, but if I take properties of 'WindowsImageBackup' then 'Size on disk' is only 176GB.

I've changed folder settings so that I can see hidden and system files, but the total sum from the files I can see is 176GB (Which seems odd as there is at least 300GB data on the server). Are there more files hidden somewhere? And if so, can they be copied someway? Or is the backup locked to this physical

Data will be compressed when backing up. Have you tried different tool to backup. If the backup files are in the same size. There is no wrong.

But I still don't see why the 'Used space' size on the disk (1,24TB), and the size of WindowsImageBackup (176GB) should differ if files were compressed. Why should the disk show any different sum than the sum of all files?

Hi,

Right click on select Properties cannot provide an accurate result. When we do not have permission on a folder or file, it will not be calculated in Properties. 

You can run a check disk on that drive in CMD which should give you an accurate result. 

There aren't that many files under WindowsImageBackup , so it's quite easy to make a rough estimate on the sum of all files (with hidden and system files visible). And there was nothing that coould account for the missing *** 1TB *** !

How are the shadow copies stored? Are they in the .VHD files?

What's the result of running a check disk on this volume?

In this situation you may also try with a third party application for listing all files on that volume. 

This application may help do this job. 

Please Note: The third-party product discussed here is manufactured by a company that is independent of Microsoft. We make no warranty, implied or otherwise, regarding this product's performance or reliability.