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I opened Computer Management and happened to see that "Local Users and Groups" (under System Tools) had a red X over top of it. After clicking the link, it shows a message saying "Unable to access the computer EMACHINES-PC. The error was: Library not registered." What could have caused this, and how can I fix it?

Thanks in advance!

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up vote 1 down vote accepted

You are probably missing the active directory store type library. You can restore it in a few easy steps:

  • Download RegTLB.exe from here.
  • Extract RegTLB.exe from TypeLibrary\Release (We'll extract it to the C:\ drive to make it simple)
  • Open up command prompt and run this command:
C:\RegTLB.exe c:\windows\system32\activeds.tlb
  • You will get a messagebox saying the type library was successfully created
  • Local Users and Groups should now open successfully.
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Yeah, I'm on EMACHINES-PC and Computer Management is local. – Wesley Feb 15 '10 at 23:49
@Wesley answer updated. – John T Feb 16 '10 at 0:07
Perfect! Thanks =) – Wesley Feb 16 '10 at 6:26

I used Filemon v6.07 and found out that a file called activeds.tlb was missing. After I restored a copy of it into the system32 directory, I was able to access the local users and groups database from the local computer's Computer Management Console again.

the utility Filemon is a monitoring tool lets you see all file system activity in real-time. Filemon works on NT 4.0, Windows 2000, Windows XP, Windows XP 64-bit Edition, Windows 2003 Server, Windows 95, Windows 98 and Windows ME. Sysinternals also has a version of Filemon for Linux. and is available at:

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How did you "find out"? – Wesley Feb 15 '10 at 23:54
It's an old thread on… but it worked good for me a while ago. Ihope it help for you. – r0ca Feb 16 '10 at 13:11

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