Missing space on NAS drive

I bought a new Mycloud 6TB drive. When I map the drive (one of the shares) in Windows 7, it only shows a drive size of 5.4TB. I would expect it to be 5.9 like the MyCloud status page shows. Where is my 1/2 TB?
There are no files in any of the shares.

The Windows Operating System may be calculating or reporting the total space differently than the Linux OS used by the My Cloud.

Edit to add: It should also be noted that a portion of the My Cloud hard drive is set aside for the My Cloud operating system. That too may account for the difference in size reporting.

I dont think linux os would take up 500gb of space.

No the OS doesn’t take up 500GB of space but it does use some. There is the following WD Support document that explains why one typically doesn’t see the full capacity size (6T for example) of their hard drive. For a 6T drive WD indicates the approximate capacity will be 5587.94 GB.

http://support.wdc.com/KnowledgeBase/answer.aspx?ID=615

So the dashboard states unformatted capacity then,I didnt know that.

No, Microsoft reports Tebibytes. The cloud dashboard reports terabytes.