Sata HDD works in external dock but not internally?

If you don't have a UEFI BIOS and / or if your OS isn't UEFI compatible, a UEFI / GPT disk will not be recognized. As BIOS makes the interface between the disk and the OS it's important to set Storage Boot and PCI device to UEFI only.
For example, Win 7 32 bits isn't compatible with UEFI / GPT, only Win 7 64 bits.
To have disks bigger than 2T, and work around this limitation, (not sure) manufacturers install a software that translate the GPT disk.
To install a GPT disk directly to the MB, you have to set UEFI on BIOS and have a UEFI OS compatible (Win 7 64bits). As Jumanji posted, the reason why you can't erase partitions can be because the owner is on a network, but I think that the problem is more related to UEFI BIOS settings and installed OS.

A Legacy Bios / MBR PC can use GPT Data disks > 2TB.
I can post a screen print if you want.

I'm not saying it's impossible. On a legacy system, there are some workaround to be implemented to work properly.
On a UEFI is plug and play.
http://www.wdc.com/wdproducts/librar...579-771501.pdf
https://support.microsoft.com/en-us/kb/2581408
Support for Disk Drives Beyond 2.2 TeraBytes (TB) and 4K Advanced Format Sectors

Hey Guys,

Thanks for your feedback, as Jumanji mentioned I was sleeping on the other side of the world haha.
I have attached screen shots of the 4TB drive whilst in the external dock and it shows only the first 2TB of the drive which you were correct on saying this is a limitation for this dock. However when I connect it internally I can see the whole 4TB in disk manager and MiniTool (see the third attachment).

I checked the mentioned settings in the bios and they were:
- SATA=AHCI
- CSM (Compatible System Mode) = enable
- Storage Boot and PCI device = Legacy (not UEFI)
- Fast boot to disable.

Also I tried to re-format the 4TB drive so it is now MBR not GPT (well only a 2TB portion of it) but I still have no change. I was thinking this may have been an easier solution for the time being rather than re-installing everything, shouldn't this have had the same effect?

As for the story of this PC and it's HDD, It's a brand new PC purchased and put together by another guy I work with, he got this far and asked me to help with this issue as I know more about this sort of thing than him but am far from an expert (obviously!). As for the HDDs the big 4TB is actually NEW and the 2TB was picked from another PC (not in a RAID), both drives work perfect in two other computers we have put them in this issue only exists on this machine. The dock we just happened to have lying around and we were using to try and problem solve. The OS is Windows 7 Ultimate x64

It turns out you are not the owner/ user with administrator privileges. Your friend Mr.X is. You are perhaps operating with a non-administrator guest account.

If your friend Mr.X trusts you, can you not log in as the original user and troubleshoot for him? That will greatly simplify matters. And during this troubleshooting process disconnect from the internet so that there is no network influence and also disconnect all other external drives including the media drives physically plugging those out ( safely remove) and also disabling your fibre channel adapter/program.

You have needlessly formatted the 4 GB drive as an MBR drive in the 4GB incompatible dock. Once you log in as the administrative user Mr.X, check whether you can read and write to 2TB as well as the 4TB (now 2TB MBR drive) drives and post your findings.In effect you will be starting afresh doing away with any unnecessary attendums that can be confusing.

As you said that you are not an expert, me too not an expert in dealing with these problems, but I think the above recommended process will put the whole thing in a proper perspective for other experts to chip in and guide you with any problems you face and report.

( Don't worry about the 4TB MBR drive. It can be reformatted as a GPT drive bringing the whole space accessible)

I am also not sure whether it is absolutely necessary that you should only use UEFI and reinstall Windows 7 64bit on a GPT SSD. Other experts to look in and advise you.

This machine has a single admin account, the same account I am logged into and using.
I have tried booting into windows with no fibre channel drives connected and also disabling it's managment software (with the internet still connected) but no change. I was told by Mr.X that this problem existed before the fibre channels were connected and configured, but I didn't see this for my own eyes I have to trust him on that.

I don't mind formatting these drives over and over again as there is nothing on them, Ive done it several times whilst in the external dock. Also on the drive (whilst in the dock) Ive also gone into properties/Security and successfully claimed ownership of the drives under the admin user I'm logged into but alas as soon as I re-boot and re-connect back the drive back into the motherboard all is lost again? and I have no access and no control... ?

Have you tried initializing the drive as GPT while it is connected to the motherboard (not in the dock) ?
You might also want to do a Diskpart Clean while it is connected to the motherboard (before initializing).

You are having all this problems because Win 7 wasn't installed as it should. Your MB deserve a clean install with UEFI, and this problem will be gone.

For me a 3TB GPT drive works with Windows installed as Legacy Bios / MBR.
I just plug it in and it works, no special drivers, workarounds, etc.

Here is a quote from the MS KB article linked in post #13

Overall requirements for a non-bootable data volume

For a system to be able to address the maximum capacity of a device that has a storage capacity of more than 2 TB, the following prerequisites apply:

• The disk must be initialized by using GPT.
• The Windows version must be one of the following (32-bit or 64-bit, unless otherwise noted, but including all SKU editions):
  
  • Windows Server 2008 R2 (only 64 bit version available)
  • Windows Server 2008
  • Windows 7
  • Windows Vista
  
  
• The latest storage drivers from your storage controller manufacturer must be installed. For example, if your system uses an Intel storage controller that is set to “RAID” mode, make sure that you have the latest applicable drivers from the Intel support site.
• Overall, you should contact your system vendor to determine whether the system supports device sizes of more than 2 TB.

Source: https://support.microsoft.com/en-us/kb/2581408