Do I need the 3 UEFI partition?

Hi all,

I have read that if I pre-partionate my SSD before the OS install (in another computer or with command prompt (diskpart) by pressing SHIFT+F10 at the region/language selection window of the installer), it won't create automatically the 3 UEFI related partitions (Recovery, EFI-system, MSR Reserved) if the drive isn't unallocated.
So three questions have born in my head immediately:
1. What are these 3 partitions actually for?
2. What do they do?
3. Do I need them at all, if I want to see only C and D drives (1 drive with two partitions) in the Disk Management?

Thanks,
hazazs

Almost all UEFI computers need a FAT32 partition to boot from. That's why a separate EFI System Partition (ESP) is required. If you boot the computer in CSM (legacy BIOS) mode, then you can have your C: drive (NTFS) partition also be marked as Active and be the system partition the computer boots from. You will be limited to a 2 TB drive, because it will also have to be MBR partitioned to boot in CSM mode.

What's the issue with having a small 100mb FAT32 system partition? It doesn't get a drive letter so it won't show up in explorer.

Windows is regularly updated.
And Windows needs to have certain parameters to have a trouble free upgrade.
There is little free space gained proportionally.
There are many websites that offer free space in the cloud and large size flash drives and hard drives are relatively inexpensive.
When you look at the pro and con its best to maintain the default partitions.

https://docs.microsoft.com/en-us/win...ive-partitions

The EFI partition is needed for the system to boot and cannot be deleted.The MSR partition is used by some software that needs scratch space. I have read that bitlocker needs it. You will probably not notice any problem by not having it, however it is normally quite small (typically 16mb) so I would keep it; Microsoft says it is needed on GPT disk.The recovery partition is needed to boot in recovery mode (I think you can still boot in safe mode without it) which is a special very small live windows system that can be used for recovery. It contains a few automated tools that rarely works as well as a command prompt that may work if you know what to do. Even if you do not have it anymore, you can still have the same functionality by booting the official windows 10 media and choose "repair computer" instead of "install". IMHO, this recovery partition is not very useful. Some OEM might use a similar partition to factory reset the computer.

Guys,
First of all, thanks for the infos (a reputation is given to everyone), but the question wasn't this: "Can I delete these partitions?"
If a drive is pre-partitionated (means there is no unallocated space on it) then the OS install won't generate these partitions at all, even in UEFI mode.
The question was: "Is this method "safe"?"
I think in this way all the required boot/recovery files will be installed on the OS (C:) drive, right?

By the way I don't really need that 615MB (499 + 100 + 16) space, simply IMO it's annoying such a lot of partitions.
But finally I think I will let the installer creating them, since it is the default (maybe the most optimal) setting for a GPT style drive.

On an UEFI installation, the boot files cannot be in the C: drive partition. UEFI requires a FAT partition to boot from and C: drive will be NTFS.

Indeed. By the way why does this new UEFI boot mode use the old FAT system?

hazazs said:

Indeed. By the way why does this new UEFI boot mode use the old FAT system?

I don't know why the UEFI specification does not require EFI System Firmware to support NTFS, but it only requires it to support FAT. See starting on page 499 here:
https://uefi.org/sites/default/files..._2_8_final.pdf