"unknown Users" are listed in Properties/Security of a folder.

PROBLEM: "unknown Users" are listed in Properties/Security of a folder.

I have Windows 7, 64-bit.

The Properties/Security box of my "C:\Users\[my name]" folder lists two Users called
"Account Unknown (S-1-5-21-879640176-2077098734-2292519611-1001)"
and, "Home Users", in addition to the legitimate Users "SYSTEM", "Administrators", and "[my name]".

After deleting the computer's Limited Acct, the 2 Users are still listed.

"S-1-5-21-879640176-2077098734-2292519611-1001" is not found by the Yahoo Search Engine. The Windows folder-specific search engine for "C:" and for "Users" searches essentially indefinitely. That for the folder named after myself finds nothing.

Especially regarding "S-...", is this caused by malware ? Would deleting either or both of these Users cause harm ?

Thanks.

Thanks, logicearth, for the solution and for the reference to Wikipedia. I removed the 2 users from the folder's Properties/Security list.

To all forum users, please consider this thread solved and closed.