I like to have simple none-spacey folder names like C:\Users\Alex of my windows login account and use login with a microsoft account. I get this by creating Local user account, login, then change to microsoft account type as specified here
How to rename the User folder in Windows 10?
Now I would like to do the same with family member, who is registered as Family Member (for Minecraft game connection) in microsoft.com. When I try to change to Microsoft account login on a second local user account it says
another user on this device uses this microsoft account
If I in User settings > Family add user account, then I get windows determined folder name. The folder name is not that bad nowadays, its non-spaced and first five letters it seems, but I would like to specify it my self.
How do I get around this? (I have one convoluted solution which I found and will post but I would prefer better solution)