Windows 10: Created a GPT Partition disk while plugged into usb

I had gotten a new hard drive in preparation to replace an old one that had been slowing down, and getting closer to the end of it's life. When i made the original partition table, i had selected GPT, not knowing what would happen afterwards.
I transferred everything from the old disk to the new, as well as some files from another disk, to keep all my games in the same place. so now the total size of the disk is more than the old one.
As soon as i insert this new drive into the computer through the sata connectors, and boot the computer up, the disk does not even show up, and when i look into disk management, it just shows up at "GPT Protected Partition" It's my disk!! that's my data!!! why can't I access it?! I've tried to use Ease US to change the partitioning table over to MBR so i could at least see the dang thing, but it says that it can't convert it because the target disk is more than 2 TB. it's a 4 TB Disk, the old one was 1 TB.
I really need some help, because i can't just move everything over again, that's going to take a whole day to get done, and not to mention, i don't want to move everything back over to the nearly dead drive just in case it decides to up and kill itself while i'm transferring things back and forth.
To summarize:
Replaced OLD 1 TB disk with 4 TB.
Created the GPT Partition table on the 4 TB drive when it was connected through USB. The old drive was still in the computer.
Transferred everything over through USB
Upon insertion of the 4 TB drive, Windows refuses to read the disk, claiming it's GPT Protected.
I cannot move everything back, no more room and i do not want the old drive to die in the middle of it.

:)

 

How do I run Scan Disk on a new computer with a GUID Partition Table (GPT) partitioning scheme (not MBR)

Windows has no problem with GPT partitions. The problem probably lies with your USB IDE/SATA adapter. I suspect that it cannot deal with GPT partitions. You could do this:

• Put the problem disk back to where it came from.
• Create a bootable flash disk with RecoveryDrive.exe.
• Boot the machine with this bootable flash disk.
  
• Open a Command Prompt and run chkdsk.

 

Convert only one partition on the disk from MBR to GPT

Follow the steps listed here on using GPTgen. He also lists how to create and restore backups.

Converting MBR to GPT without deleting your partitions

 

Can not install Win10 preview on GPT partition

I have been dual booting with win 8.1 & win10 insider preview. It was a few builds old and haven't been getting new builds. So when the new 257 iso came out this week I tried to install over. It had issues with the disk being GPT so I rashly deleted the
win10 partition to start over.

I've created a iso usb and made it a gpt as has been suggested but it just wants to install win10 without asking which partition it wants to install on, so I cancel it as it looks like it would delete my main win8 partition.

What format should the usb iso be created under, GPT or MBR?

The bios is in EFI so shouldn't I just plug in usb iso, reboot and it will run the setup asking which partition I want to install to?