Format EFI Partition in Windows

Question

I have a laptop with an SSD (Disk 1) with Windows, and a HDD (Disk 2) for Data. A while ago I installed Linux with dual-boot on the HDD but at some point it broke so I just format the Linux partition from Windows leaving an unallocated partition.

The problem is that I cannot do the same with the EFI system, the option to format it is greyed out.

• How could I format the EFI partition?

• Is there any danger of deleting it? considering that the Windows partition has its own EFI partition?

• Moreover, when I try to extend the DATA(D:) Partition with the unallocated space it says that it would transform into a dynamic partition. Is this due to the EFI partition in the middle?

Here is a screenshot of the Disk manager:

And some other information in case it is relevant: Laptop ASUS FX505GD Windows 10 Home, Version 21h2, OS build 19044.1586 Intel(R) Core(TM) i5-8300H CPU @ 2.30GHz 2.30 GHz

I'd be happy to provide any other relevant information.

EDIT:

• following @user1686 recommendation, I assigned a letter to the EFI partition but when I tried to open it says: "You don't currently have permission to access this folder, Click Continue to permanetly get access to this folder"
• but when I press continue, another pop-up says: You have been denied access to this folder. To gain access to this folder you will need to use the security tab.
• I cannot find the security tab in the properties for the partition.
• I tried changing the partition id to ebd0a0a2-b9e5-4433-87c0-68b6b72699c7 from diskpart (previously it was c12a7328-f81f-11d2-ba4b-00a0c93ec93b which I understand correspond to a hidden partition) but still cannot access the mounted partition.

Answer 1

Is there any danger of deleting it? considering that the Windows partition has its own EFI partition?

Likely not, but depends on what's inside – you should assign a drive letter to it and look at what files it contains. EFI partitions have no hidden boot sectors or anything like that; they only deal with plain files.

If the EFI partition was created by Ubuntu, it will only contain GRUB and Shim, which are unneeded by Windows and can be deleted. You can start by deleting just the individual files belonging to Ubuntu, then if the partition remains empty, delete it whole.

On the other hand, if you see a 'Microsoft' subdirectory, or the 'bootmgfw.efi' and 'BCD' files – those belong to Windows and are necessary for Windows to start. (However, they could be moved to another disk if necessary.)

Always have a Windows install USB stick ready – it can be used to create a fresh EFI partition and reinstall a fresh bootloader using bcdboot.

How could I format the EFI partition?

Use diskpart.

But in this case it sounds like you want to delete the partition, not to format it. There's no point in formatting a partition that's just going to be deleted the next moment.

1. In diskpart, use list disk and sel(ect) disk ### to select a specific physical disk – their numbers are the same as in DiskMgmt.

2. Then use list part(ition) and sel part ### to select a specific partition on the current disk. Yours will probably be partition 2 on disk 0.

3. Use detail partition and detail volume to get more details about what is currently selected.

4. To delete the selected partition, use del(ete) part override – make very sure you have the correct one selected, as there's no confirmation at this point. (It's the 'override' keyword that allows deleting EFI partitions and other reserved partitions.)

5. (To format the selected partition instead, use format quick fs=ntfs or fs=fat32 – again, there is no confirmation, it just immediately proceeds with trimming and formatting. But note that this won't unmark the partition as "EFI system partition".)

Moreover, when I try to extend the DATA(D:) Partition with the unallocated space it says that it would transform into a dynamic partition. Is this due to the EFI partition in the middle?

Yes. Standard partitions must be contiguous – both the MBR and GPT partition table formats only allow specifying one "start–end" range for any partition, it cannot skip over another partition in the middle.

("Dynamic" partitions use Microsoft's 'Logical Disk Manager' partition table format, which is a lot like LVM that's found on Linux, and both have support for joining multiple chunks into a single logical volume.

Microsoft now recommends avoiding dynamic partitions, though – their own documentation says they're only keeping the old technology in for a few specific cases that the newer Storage Spaces can't handle. So if possible, stick with simple GPT partitions.)