This post is a quick technique used to show how to slap the DFS Management snap-in around when it acts foolishly. The snap-in is writen for optimal performance by caching new expensive data from LDAP. This optimization prevents the management tool from over utilizing the network with unnecessary queries. The snap-in recognizes when information is new and remembers it. However, the behavior changes when we delete information. Find the cache location: %appdata%\Microsoft\MMC ; open the listed path, that expands to a folder within your profile: C:\Users\nedpyle\AppData\Roaming\Microsoft\MMC ; you'll see a ‘dfsmgmt’ file without a file extension. Close the DFS Management snap. Then delete or rename the dfsmgmt file. Start the snap-in. Done!
Source:→ DS Team Blog