What is MSR partition?

Question

I was trying to reinstall windows but on the step "Choose a Physical Location to Install Windows On" I stumbled upon this MSR partition I knew nothing about. What is it for? Am I to delete it or leave it as it is? Which partition should I choose on this step?

Answer 1

Borrowing from gronostaj's answer:

It's a placeholder invented by Microsoft. It doesn't contain any meaningful data and it's there just in case you'd ever need to create some additional partition for special uses. In that case, Windows will shrink the Reserved partition and create a new one in the recovered place. Deleting it shouldn't do any harm now, but you may face some problems in the future.

Then we have some information in microsoft's faq:

The Microsoft Reserved Partition (MSR) reserves space on each disk drive for subsequent use by operating system software. GPT disks do not allow hidden sectors. Software components that formerly used hidden sectors now allocate portions of the MSR for component-specific partitions. For example, converting a basic disk to a dynamic disk causes the MSR on that disk to be reduced in size and a newly created partition holds the dynamic disk database. The MSR has the Partition GUID:

DEFINE_GUID (PARTITION_MSFT_RESERVED_GUID, 0xE3C9E316L, 0x0B5C, 0x4DB8, 0x81, 0x7D, 0xF9, 0x2D, 0xF0, 0x02, 0x15, 0xAE)