Windows 10: Unknown user

I want to share a folder to other LAN-computers.
Have Windows10 Home with all updates.
When checking the users for that shared folder I discovered an unknown user ... how do I remove this guy?

:)

 

Unknown User Account created after upgrading to windows 10. It comes back if I delete it.

Original Title: Unknown User Account

Hello,

Since I upgraded to Windows 10 I am seeing an account that I did NOT create. So I deleted it by going into Control Panel > All Control Panel Items > User Accounts > Manage Accounts then I click on the unknown user account and delete it. That said.... It
comes back. I have also followed the below suggestions from other posts and still does not seem to work.

Let’s try simple steps and check if the user account is detecting and try removing it.

• 
  Press Windows key + R, type netplwiz and press Enter.
  
• 
  Check if the user account is appearing on the list.
  
  
• Click on user account and click on Remove. (If user account appear on the list).

Please advise.

Thank you

 

Current active users that are friends

The other reason I suggested this is that users can add characters to their username that are not alphanumeric (e.g. user*). This confuses things somewhat when looking at the list.

 

File LOCKED by UNKNOWN User

I've tried your suggestion, but continue to get: "Locked for editing by Unknown User". The document is an OpenOffice4.1.3 Calc document (.ods). Any other suggestions?

EDIT 3.Dec.2016: Problem resolved
with additional help from OpenOffice Forum.