If you configure Terminal Services to reset idle or disconnected sessions, when you attempt to re-map a DFS drive, you receive:
System error 85 has occurred. The local device name is already in use.
The problem is likely to be a time-out value which is too low.
Starting with Service Pack 3, you may extend the time-out:
1. Use the Registry Editor to navigate to:
2. Add Value Name LogoffTimeout, a REG_DWORD data type, and set the data value to a number between 90 and 449. This number is in two second increments. A data value of 120 is equivalent to four minutes.
3. Open a CMD prompt and type:
net stop termservice
net start termservice