Hi Jon, welcome to the Eight Forums.
The user profile with SID (security identifier) ending with 1001 is usually (not always) the first user account created when Windows is installed or a pre-installed Windows booted first time. In most cases this means it's your own user account.
You can check for which user account that SID belongs by giving the following command in Command Prompt:
This example from my laptop, the first account I created when I installed Windows 8.1 was a local account called Admin which got the SID 1001:
wmic useraccount get name,sid
SID ending with 500 belongs always to the built-in administrator account, SID ending with 501 to built-in Guest account, whether these two accounts are enabled and active or not. Other user accounts start from 1000.
What the above means is that you have most probably tried to remove your own account. Don't do that !