Space Consumed, Missing Files on server HDD

Hey,
I've had a look around a lot of forums but cannot find anything to solve my specific problem.
I have a home server setup, cloud server if you will, and I had all my pictures, music and videos on the hard drive installed, the system worked perfectly fine. During the day i had made a couple new user accounts and done a couple firmware updates and when I went to access the files later they had all disappeared, yet i could still see the space on the HDD was consumer.
I read someone else post about their HDD be hijacked and permissions being changed and thought this may be my problem, so I have now taken the HDD out of the server box and connected it directly into my computer guessing that there may have been some permission issues, only to find that there is not security tab? my other permanently internal HDD's however do have the security tab.

I am running Windows 8 and have looked and looked for ways to change permission on this HDD without any luck...
Server is a Terramaster U1.
HDD is a 2TB Western Digital, I have owned for a while with no problems.

Currently i am running both Recuva and Zero Assumption Recovery on the HDD to see what they come up with.
Hope someone can help me.

Regards,
Matt