Windows 10: Windows 10 Clean Install still applying old account unknown S-1-5-21-********** permissions...

Any help would be appreciated with this. I have also mailed a letter to Microsoft Corporate offices in WA attn: Complaint Department. Really do not know what else to do. Ignoring the Account Unknown is not a valid solution in my case, and does not solve the actual problem, and if I have to do a fresh installation again, I will have to go through the process of granting myself permission to any connected drives, and network resources. I also lose access to OneDrive folder installed on separate storage device from OS, and have to add my Microsoft account as administrator to re-enable access.

I would also like to note that using my Microsoft account when installing Windows on this particular computer, results in invalid network credentials accessing any shared drives on other Windows 10 installations using the same Microsoft account on ALL. The only workaround is to use add a local account on the other computers to be able to access their shared drives. Microsoft support considered this *Solved*, despite them recommending to not use a local user account. I have 5 PC's with Windows 10 Pro, and 2 PC's with Windows 10 Home tied to my Microsoft account. This particular PC is the ONLY one that shows this S-1-5-21 Account Unknown in any of the permissions.

It appears the issue is with credentials associated with my Windows 10 digital license, but tech support has transferred me to Activation and Licensing, and A&L said that it was a Tech Support issue. After being connected to TS, they informed me that I needed to be transferred to A&L. I have also been provided two separate tech support numbers for Microsoft Support, despite me telling me informing them that it instructs home users to initiate support through help.microsoft.com. The pattern seems to be when outsourced tech support cannot fix the issue and has been on the phone too long, the directive is to just hang up the phone. I seems that Microsoft is using the same support centers as Comcast.

And just to be crystal clear, I even disconnected all SATA drives except for Primary SSD, deleted all partitions and installed the OS. I only did this because an inexperienced Microsoft Advisor was persistent that I had a virus and must perform virus scan. Geez. Anyway, that obviously did absolutely nothing after performing another clean install.

:)

 

Account Unknown has full Security permissions on my own User - huh?

Account Unknown(S-1-5-21-1345748419-2493160549-2943627078-1000)
has full permissions in the "Advanced Security Settings" for my own user account on my Win 10 Pro 64-bit PC.
What is it? Is this normal?

If I go to C:\Users\ , it lists four users:
[Myself]
Default
Default.migrated
Public.

If I right-click on [Myself] and hit Properties, then go to the security tab, it lists four "Group or user names:" with certain Permissions:
SYSTEM with full permissions - all items checked
Account Unknown(S-1-5-21-1345748419-2493160549-2943627078-1000) with the same full permissions - all items checked
[Myself] with the same full permissions - all items checked
Administrators with the same full permissions - all items checked

What is the Account Unknown(S-1-5-21-1345748419-2493160549-2943627078-1000), and how did it get there?

Two clues:
1) My PC is dual-booting Win 7 Pro 64-bit and this Win 10 Pro 64-bit. I'm in the Win 10
2) 15 minutes ago (and before checking this), I turned on Public file sharing so other PCs on my home network could see any documents I put in those Public folders or maybe vice versa. I do NOT have "Homegroup" turned on.

But wha' happening here?

 

Account Unknown (S-1-5-21-130066488-785734366-1129733132-1000)??

Hi, recently whenever i have checked the security tab of my files, I see the above thing: Account Unknown (S-1-5-21-130066488-785734366-1129733132-1000), should i worry about this?? a hacker or something?? how can i delete this, it has "special permission". Also there is another account similar to this under INTERACTIVE, whats going on?? Hope someone can help. Thank you.
Keith

 

S-1-5-21-119163587-1573839180-90999006-1001

I give up, what is it - and what's a "security ownership panel?"

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FYI...

Well-known security identifiers in Windows operating systems:

https://support.microsoft.com/en-us...rity-identifiers-in-windows-operating-systems

Unknown User in security settings s-1-5-21 ... 1001

Unknown User in security settings s-1-5-21 ... 1001 - Can someone please review? - Virus, Trojan, Spyware, and Malware Removal Help

Account Unknown (S-1-5-21-130066488-785734366-1129733132-1000)??

Account Unknown (S-1-5-21-130066488-785734366-1129733132-1000)?? - Windows 10 Help Forums

How to understand the anatomy of security identifiers

How to understand the anatomy of security identifiers