What threatens the absence of an MSR partition?

Question

Windows

It was necessary to put Windows 10 on an external drive. The Windows installer does not allow you to do this in the standard way, I had to use the WinNTSetup utility.
Installing Windows 10 for GPT using WinNTSetup does not create an MSR partition.

There are 2 questions:
1. Did I do something wrong in WinNTSetup, that I installed Windows on an external drive without an MSR partition?
2. If I use Windows on such a drive, where there is no MSR partition, what is the risk?

Answer 1

The absence of an MSR partition on a GPT disk is fraught with non-working updates.
I came across both on windows 10 and on server windows. As soon as you create a partition, it starts updating normally. Apparently some updates use it. But not everything is a fact.
But for the OS to work from an external drive, additional manipulations are required. The system may not see the disk, for example, due to late USB initialization. Google ... everything is there.

Answer 2

The MSR partition is not required for windows to work, it will only appear when you select the type of disk partitioning gpt, it may be needed for tasks that cannot be performed from the working system (since I didn’t have such a partition, I don’t know what it is, google it) from this partition the system will launch a mini version of itself.
ps running windows from an external usb drive is an abnormal (read forbidden) situation, you will almost certainly have problems creating a swap file, installing drivers in a regular way, or something else. The update won't install either.