WD My Book 3Tb - becomes as 800Gb

Brand new WD My Book 3Tb. I’ve wrote about 1.5Tb media-data and connect to ASUS DSL-N55U via USB. After data indexing, ASUS DSL-N55U shows WD My Book 3Tb as 800Gb disk, and about 700Gb media-data were lost. Now when I’ve connected WD My Book 3Tb to PC, I see only 800Gb disk space.


DISKPART> detail volume

Disk 3 Online 2795 GB

Volume Capacity : 747GB

Volume Free Space : 4978 MB

So - DISKPART sees the disk as 3Tb, but with volume only 747GB.

Technical’s Gurus - who can understand what’s up with my 3TB disk?

And how to recover the disk (and how to avoid such surprise in future?)



First up check to see if you have a UEFI BIOS.

next check the partition on you drive make sure it is a “GPT disk”

to check right click on my computer>manage>disk manegement

then right click on the disk where is says disk 1…and a graph. try to convert to GPT. remeber to back up first.

Hi Gazzi,

What does it mean - UEFI BIOS?

What I have to check in the BIOS?

Regarding “GPT disk” -

No  - the disk is mark as MBR Disk. And what is more - I worked with this disk during about the week (when the 3Tb disk was connected directly to my notebook Sony VGN-Z530N). No errors with this MBR Disk. But when I’ve cinnected the disk to the ASUS WiFi ADSL N55U - the disk format was corrupted and part of my data were lost.

So the first question - how to restore the original (3Tb) disk format?