Two identical external drives with the same files and 70 GB difference of USED SPACE

So I had one Seagate MyBackup 1TB and then I bought an identical one to make an identical copy of all the files.

FIrst I used a tool called Cobian Backup, but it didn't work right and I just copied the files directly after formatting the new one with the same NFTS and 4096 bytes.

So, there is a difference of 70 GB, a hell of a lot, between the two. The older drive is the one taking more space.

I could understand a slight difference for unknown trechnical reasons, but 70 GB is a HUGE difference.

I defragmented with Defraggler and with Windows and both say it is 0% fragmented. The disk capacity is identical, 931 GB for both, so there is no hidden partitions as far as I know. I also checked by showing hidden files and nothing was found.

Anyone?

 

There are two possibilities here:

1) (Less likely) The Cluster Size for your two disks is not equal, and you have a ridiculously high number of very small files being stored on these two disks. However, this is not likely, because (a) you stated the cluster size as 4K, which makes me believe you know what cluster size is; and (b) you would need 17+ million files on 4K clusters to cover 70GB difference.


2) (More likely) You have hidden files / folders on your older disk, to which you do not have read permissions to. You can test this by selecting all files / folders, and going to (right click) --> Properties. Do this for both disks, and see if the Used Space count is identical for both disks. If you did a drag-and-drop copy, they should be. If they ARE equal, then you are in a situation where you have hidden files / folders on your old disk. If they ARE NOT equal, then your drag-and-drop copy did not work perfectly, and you need to start tracking down the differences between the files on the two drives to pin down where the difference is.

 

Thanks a lot for replying. It's maybe the second option. The cluster size is the same 4k and it is ONLY mkv movies around 800MB average size, no small files, zero.

In the screenshots below you can see they are the same number of files, same number of MB but different used space.

Should I format disk 1 and that will solve the problem of that "hidden partition"? Probably caused by this Cobian Backup thing I used first.

 

Yes. Looks like the problem is hidden files on Disk #1 (old drive).

There are two things to try:
1) Run a checkdisk (chkdsk) on your E: drive to see if the space is being used by lost sectors or orphaned files.
2) If that doesn't work, then go into Windows Disk Manager, delete all partitions on E:, re-create them, and then drag-and-drop your content from F: --> E:

 

Thanks a lot.

Chekdsk says it's perfect, so I guess I'll just format and copy all movies from #2.

DO you know if a normal quick formatting is enough? And do you know what cluster size is better for ONLY movies (size 700MB-1GB each). I just dont use it for any other files but movies.

Thank you!

 

For this, I would go into Disk Manager and delete / re-create the partitions from scratch. It only takes an extra 30 seconds on top of doing a quick format.

Once you re-create the partition, format it as NTFS with default cluster size (probably 4KB). You should be fine from there.

 

Great. A million thanks for everything.