Mystery SID. Help plz.

When I find, and then search, an unknown user in my computer, and nothing comes back, I worry.

S-1-5-21-2345238457-1554497050-1494753864-1000
Is this defaultuser0, my alter-ego?

This is me:
S-1-5-21-2345238457-1554497050-1494753864-1001

So, who is this defaultuser0?
S-1-15-2-2434737943-167758768-318...
Cloudexperiencehost,, which I found in windows10 Firewall, inbound.

I HAVE FOUND 2 DIFFERENT SID'S FOR defaultuser0!

I am just learning, so bear with me, but I am on a quest to get to the bottom of ANY user on my computer that I have not authorized: I am tired of changing my settings BACK to the way I set them, and, just maybe, defaultuser0 could be responsible.

Correct me, if I am wrong, or say "me too".

Open Command Prompt or PowerShell, enter command wmic useraccount get name,sid. This gives you a detailed list showing which SID belongs to which user account.

Kari.