My 3TB HD converted to EFI Partition

Question

I have 3TB HD installed in my pc. I dont know how its converted to "EFI system partition" !! Can I return it back to normal patition without formating or cleaning it? This picture shows that disk 0 is completly an EFI partition

Answer 1

It may be as simple as changing the partition type back to “Microsoft Basic data partition” (ID EBD0A0A2-B9E5-4433-87C0-68B6B72699C7). This could be accomplished easily with a number of partition tools on Linux:

fdisk (newer GPT-capable versions)

1. Identify disk: fdisk -l
2. Start editing: fdisk /dev/sdX, where sdX is the correct disk as identified in step 1
3. Change type: t↵, L↵, enter code for “Microsoft basic data” from list (11 on my machine), ↵ (nb: because there is only a single partition, we won’t be asked which partition to use)
4. Save changes: w↵

gdisk

1. Identify disk: Run gdisk -l /dev/sda, gdisk -l /dev/sdb, ... until you find the disk
2. Start editing: gdisk /dev/sdX, where sdX is the correct disk as identified in step 1
3. Change type: t↵, L↵, enter code for “Microsoft basic data” (0700 on my machine), ↵ (nb: because there is only a single partition, we won’t be asked which partition to use)
4. Save changes: w↵, y↵

parted

1. Identify disk: Run parted -l
2. Start editing: parted /dev/sdX, where sdX is the correct disk as identified in step 1
3. Change type: toggle 1 msftdata↵ (nb: changes take effect immediately)
4. Quit: quit↵

You could also use the file command to try and determine if it’s still NTFS:

file -s /dev/sdX1

All of the above needs to be run as root.

If you don’t have a live-bootable Linux available, I recommend using a lightweight image like Gentoo’s minimal install (boots directly to terminal, recommended) or Puppy Linux.

Answer 2

I wonder why nobody mentioned of the Windows-builtin diskpart when talking about changing the partition type GUID:

select disk 0
select partition 1 [Could be partition 2 because there is a (hidden) MSR partition before it]
set id=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

(https://en.wikipedia.org/wiki/GUID_Partition_Table#Partition_type_GUIDs)

or

set id=7

if it is an MBR disk.

(https://en.wikipedia.org/wiki/Partition_type#List_of_partition_IDs)

Answer 3

You must use a partition recovery software. I would suggest Test Disk, which is free and reliable.

Also, this answer may be useful for you.