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

Are these files that you have copied from another computer or even a previous install of Windows on the same computer? It might be pointing to a user that was on the system where the file came from that is not on your computer.

I have never reinstall any windows since my purchase, and there were no such anomaly before.......

thanks!! so i guess i can just ignore them??

keithktam said:

thanks!! so i guess i can just ignore them??

@keithktam, looking through the registry of my current machine I find entries under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Group Policy\DataStore that may help explain your unknown account.

I have four accounts on my machine and there are four corresponding keys here, \S-1-5-21-nnnnnnnnnn-nnnnnnnnnn-nnnnnnnnnn-1000 to ...-1003. Each one has a sub-key ...\0 containing the string szName. These holds the values "Computer\User" where "Computer" is my machine's name and "User" is the name of each of my user accounts. I have never deleted an account on this machine, but on another machine where I have created new accounts and deleted old ones those keys now start at ...-1003.

The '-nnnnnnnnnn-nnnnnnnnnn-nnnnnnnnnn-' part of the SID is unique to each machine, if this part of your 'unknown account' is the same as the current ones then it was probably a local account on your machine. From the '-1000' part we can deduce it was the first account set up when Windows was installed. The most likely explanation is that since Windows was first installed new account(s) have been created then the initial account deleted. If this is indeed the case then you can safely ignore it - that account no longer exists.

Bree said:

From the '-1000' part we can deduce it was the first account set up when Windows was installed. The most likely explanation is that since Windows was first installed new account(s) have been created then the initial account deleted. If this is indeed the case then you can safely ignore it - that account no longer exists.

Sometimes when you install windows it creates a user defaultuser0 with the -1000 suffix. It needn't necessarily be a user you personally created.

Like you say you can ignore it.

thanks everybody!!!