Half my 4 TB HDD is unallocated, What Do?

Solution
Assuming your Win 10 OS (I'm assuming that's your OS) is reasonably up-to-date you can probably use the Win 10 built-in MBR-2-GPT disk conversion tool to convert the drive to GPT. Do a Google search for info on accessing & invoking that command. The basic command is: mbr2gpt /convert /allowfullos
Assuming your Win 10 OS (I'm assuming that's your OS) is reasonably up-to-date you can probably use the Win 10 built-in MBR-2-GPT disk conversion tool to convert the drive to GPT. Do a Google search for info on accessing & invoking that command. The basic command is: mbr2gpt /convert /allowfullos
 
Solution