There are several reasons why you might end up with a protected partition you can’t delete on a drive. For example, some OS/Applications create partitions at the start of a drive when you write set up files.
The Windows Disk Management tool can’t normally delete these partitions, and you’ll see the “Delete Volume” option grayed out. There’s still a way to remove the partition, but it’s hidden.
This process will actually wipe the entire external drive. You can’t simply remove the EFI or GPT partition and leave any other partitions alone — you’ll be wiping the drive’s contents and starting afresh with a new partition table. If you have any important files on the drive, be sure you have copies of them before you continue.
Note the Disk Number
You can’t actually use the Disk Management tool for most of this, but you can use it for one thing. Note the number of the disk you want to remove the partition from. For example, in the screenshot below, the external drive we want to wipe the partition from is “Disk 2.” It’s actually the third one in the list, but that’s because the first disk is “Disk 0” and the system counts from 0. Remember this number for later.
If you haven’t open the Disk Management tool yet, you can do it by pressing Windows Key + R, type diskmgmt.msc into the Run dialog, and press Enter.
Wipe the Drive’s Partition Table
You’ll now need to wipe the drive’s partition table entirely. This will remove the EFI or GPT partition as well as all the other partitions on the disk, erasing the drive. You’ll lose everything on it, and you’ll have to re-partition it later.
To do this, open a Command Prompt window as Administrator. On Windows 8, 8.1 or 10, right-click in the bottom-left corner of your screen and select “Command Prompt (Admin).” On Windows 7, search the Start menu for the “Command Prompt” shortcut, right-click it, and select “Run as Administrator.”
Type the following command and press Enter to run it:
This launches the diskpart command-line utility used for advanced disk partitioning tasks. You’ll see the prompt change to “DISKPART” after you do.
Type the following command to view a list of attached disks on your computer. Note the number of the disk with the EFI or GPT partition. If you used the Disk Management utility to find this number earlier, it should be the same number:
Type the following command, replacing # with the number of the disk you want to wipe:
select disk #
For example, the disk we want to wipe in the example here is Disk 2. Therefore, we’d type “select disk 2.”
Be very careful that you select the correct disk number. You wouldn’t want to accidentally wipe the wrong disk.
Warning: The below command effectively wipes the drive. You’ll lose all the files on any partition on the drive. Be sure you’ve selected the correct disk number before continuing!
Lastly, run the following command to remove all partition information from the drive. This “cleans” all partition information from the drive, effectively wiping it and turning it into one big, unpartitioned chunk of space:
After the clean command finishes, you’ll be done. All the partitions — including EFI of GPT protected partition — will be wiped from the drive. You can leave the diskpart prompt with the following command, and then close the Command Prompt window:
Create New Partitions
Head back to the Disk Management utility and you’ll see the drive is one big chunk of “Unallocated” space. Right-click the drive’s name and select “Initialize Disk.”
Choose either the GPT or MBR partition style for the disk and it’ll begin to function like any other disk. You can then create the partitions you want on the disk, free from the EFI or GPT protected partition that appeared stuck to the front of the disk before.
If you ever end up with a drive containing partitions you can’t delete — or if you just want to start the partitioning over from scratch — use the diskpart command to “clean” it!