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Unknown user account

    Question

  • I have Windows7 RC on my system, earlier i had windows xp SP2. Recently i noticed an unknown user account (S-1-5-21-XXXXX......) in the security tab of few of the folders/files. But this user does not show up in the local user group in the control panel. Any idea what this account is and how to remove it?
    Monday, November 02, 2009 6:52 PM

Answers

  • Hi,

    @Cooladi Actually, this issue is caused by File system ACLs(Access Control List) on the harddisk, but since the account is deleted it can't be resolved to a username.

    You can try to use Microsoft Utility Tool (SubInACL ) to remove them.

    @Joesync Maybe a software/service sets a specific user account on these pic files, after changing OS or remove this user account on the computer, they also cannot be resolved.

    Hope it helps.

    • Marked as answer by Robinson Zhang Monday, November 16, 2009 6:19 AM
    Wednesday, November 04, 2009 2:51 AM

All replies

  • Hi Cooladi, 

    It is user account on previous Windows XP SP2. You can simply remove it in ssecurity tab. First, please take ownership of the folder/file if necessary. Then, click Edit, choose unknown ID, click Remove.

    Hope it helps.
    Tuesday, November 03, 2009 8:24 AM
  • Robinson, Thanks for the reply. There are too many folders/file that have this unknown user, is there any way to remove this user at system level instead of folder/file level. I tried removing at the drive level, but its still there. Any registry update/deletion would do the trick?

    Also why did this user exist on the system in the first place, i did a fresh install of Windows7 RC and on the same system partition that previously had XP, just curious!!
    Tuesday, November 03, 2009 6:19 PM
  • I found this thread searching for the same thing.

    I noticed all my Image files in documents/pictures have this unknown user when you go to properties>security. It only has Read permission. I checked some other files and didnt see it, but it may exist on others. I thought it was just weird that it was on all the pictures. Doesnt make sense at all, why would this errornous user be a part of the system?

    This is a fresh install of windows 7 64. Retail

    I has vista 64 on teh disk before this

    Tuesday, November 03, 2009 6:39 PM
  • Hi,

    @Cooladi Actually, this issue is caused by File system ACLs(Access Control List) on the harddisk, but since the account is deleted it can't be resolved to a username.

    You can try to use Microsoft Utility Tool (SubInACL ) to remove them.

    @Joesync Maybe a software/service sets a specific user account on these pic files, after changing OS or remove this user account on the computer, they also cannot be resolved.

    Hope it helps.

    • Marked as answer by Robinson Zhang Monday, November 16, 2009 6:19 AM
    Wednesday, November 04, 2009 2:51 AM
  • I hate it when people use the word "simply", and on this case, it isn't. I've tried doing the same, however, I have a TON OF FOLDER AND FILES, and NO WAY to do this to EVERY ONE AT ONCE. Is there actually a "simple" way to completely remove or replace this previously-known-but-now-windows-has-no-clue-who-or-where-the-user-came-from-but-will-label-it-with-really-unhelpful-and-long-one-line-letter-followed-by-a-massive-set-of-numbers-that-requires-a-google-search-not-bing-to-figure-out username?
    Saturday, December 25, 2010 10:53 PM
  • I've been having the same problem with Account Unknown (S-1-5-80-2375682873-768044350-3534595160-1005545032-2873800392). It keeps showing up every 6-7 days as a object in my own c:\user\rayooooh home directory with read writes. I just simply remove it from the permissions object list for that folder which also automatically is inherited by all sub-folders. So it's easy enough to remove but damm hard as hell to figure out a permanent fix. I use Windows 7 SP1.

    Friends keep posting comments as this needs a solution that is easy to apply. -Rayooooh

     

    Wednesday, April 27, 2011 7:38 PM
  • I have this situation existing as well on Windows 7 Pro 64 bit. I find it very interesting that this issue has existed since the Release Candidate of Windows 7, and the only solution given thus far is one where the administrator has to go folder by folder, file by file to remove it. Surely Microsoft can do better than this. 

    Regards,

    Lon

    • Proposed as answer by dblhelixman Thursday, February 07, 2013 6:40 PM
    Saturday, January 14, 2012 6:04 AM
  • Are you running ICloud service, have Itunes sharing to network, sharing your drive or folder to other computers in workgroup or network, sharing to a Xbox (via Media center extension)?  If you say 'yes', that might be your unknown user; Its not a literal person, its the other machine on your network.  If you say 'no', get a network management software to see if you have any intruders or check your  routers logs.  
    Saturday, February 09, 2013 4:18 PM
  • yes this seems to be correct, i also started noticing these unknown accounts on certain folders as far as i was able to figure out it happens when you use other devices which connect to your computer in some way , either data transfer or media streaming, i have 4 unknowns , i deleted one of them and again after streaming a movie to ps3 it appeared back, i also have xbox, tablet and iphone all of which have access to media folders such as music , pics and video , so im pretty sure this is the cause, hope this clears up some others questions as it was puzzling me for months.
    Wednesday, February 13, 2013 9:43 PM
  • I'm seen this 'problem' many times ...

    I restore windows due to a reinstall required, new C: drive etc

    restore files from my backup

    If the username I have just created does not match the username when the backups where taken it comes up as S-1..... - unknown

    The trick is to use the SAME username as when the backups were taken - Case Sensitive ...


    Colin

    Saturday, January 18, 2014 11:44 PM