This tutorial explains how to fix the error below. This error can be seen on any operating system, including Server 2003, Server 2008, Server 2012, Windows 7, Windows 8, & Windows 10. It can be seen on a Domain Controller, or on a server or workstation with Remote Server Administration Tools installed on it. This message appears when opening a variety of MMC snap-ins, including Active Directory Users and Computers and Sites and Services.
Naming information cannot be located because: Library not registered. Contact your system administrator to verify that your domain is properly configured and is currently online.
To fix this error, you need to use the tool regtlibv12.exe, which is provided with the .NET Framework. Open a command prompt as administrator and browse to "C:\Windows\Microsoft.NET\Framework\VERSION\", where version is the directory name of the most recent version of .NET Framework you have installed. In my example, v4.0.30319 is the most recent. Then run the following command:
regtlibv12.exe activeds.tlb
You will see a confirmation stating "Registration of activeds.tlb successful. After this, you should be able to run any of the snap-ins without receiving errors.