I have installed a new HDD, Disk 2 below. From the start it showed up as two unallocated spaces. The only not greyed out choice was to format the first allocated space so i did. Now i want to extend the formatted one to also include the unallocated space but the option is greyed out. I cant format the unallocated space. What to do?

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Your disk has the legacy MS-DOS/MBR partition table, which can only allocate up to 2TiB.

To use the rest of your disk, you'll need to convert or reformat with the new GUID Partition Table (GPT).

Microsoft has provided two ways to reformat your disk with GPT, but you will lose all your data in the process.

There are some third-party solutions that may be able to convert from MBR to GPT in place.

Here are my preferred ways to convert a MBR disk to a GPT disk because all you have to do is run one command:

Windows: gptgen

If you have a different disk, replace 2 below with the number of your MBR disk shown in Disk Management or in list disk in diskpart.exe:

gptgen.exe \\.\\physicaldrive2

Linux: sgdisk

Find your MBR disk using lsblk -p if necessary and then run:

sgdisk -g /dev/sdb

… where /dev/sdb is your MBR disk.

  • I did it the Microsoft way ("To change a master boot record disk into a GUID partition table disk using the Windows interface") since i had no data on the disk. Thanks – BERA Feb 7 '17 at 13:01

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