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How To Clear Orphan Network Drives

Sometime Windows gets confused. After a power outage, switch failure, crazy network card packets, dhcp availability or for no reason at all, you can have network drive letters that conflict with needed drive letters and you can't get rid of these orphans.

In one case after a power issue,  I saw the usual drives from logon scripts get remapped as 'removable drives'. This netbios naming conflict resulted in home drives not mounting and no access for users. Needless to say, they were annoyed.

Three solutions:

  1. Flush and reset the Netbios Cache to avoid the time it takes Windows to sort out that these drives actually don't exist. They will drop out as Netbios cleans up. This takes anywhere form 15 minutes to half a day. Sometimes these drives hang around for a very long time.
  2. Change the Logon script drive letter. The default Home drive for Windows users is H:. This can easily conflict if you have many other devices attached to the computer or in the scenario outlined above. Change the drive letter to W: for the %HOMESHARE%. I doubt you'll have that many other devices mounted.
  3. Edit the Windows Registry to remove these orphans right away. Regedit,exe is fussy so backup your registry file before making any changes. Here's how to do it:

    Navigate to the HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices section of the Windows registry.

    Locate the mapped network drive that you want to clear. Each drive will have a registry entry labeled as "\DosDevices\" followed by the letter assigned to it.

    Right-click on the drive entry and select the "Delete" option from the contextual menu, then confirm your decision to remove the mapped drive letter assignment.

    Restart your Computer to reread the Registry.

    NOTE: If you still see removable drives after the restart, you may have to check and remove any USB devices to force Windows to reset the USB Bus cache.

You can be a hero to your users if you run the Logon script on the desktop to avoid a restart. From othe dos prompt type: '//<server>/netlogon/<logon_script>'. Substitute your windows server for the <server> and the <logon_script> for the user logon script. Windows default logon script name is 'default.cmd' or 'default.bat'.

USB Drive Letter Conflicts with H: Drive

Recent computers have several flash and usb drive slots. Windows 7 may have reserved those drive letters for 'Removable Storage'. You will find that the H: netowrk drive cannot be mounted and you receive an 'Error 85, name already in use' message.
You could remove the registry entry, but those drives will persist after a reboot. You must remove or change the drive letter reservation under 'Storage'.
  1. Right click on 'Computer'
  2. Select 'Manage'
  3. Select 'Storage'
  4. Right Click on the Conflicting Device
  5. Select Remove or Change to clear the conflicting drive letter.
  6. Restart the computer
  7. Your H: drive should now be assigned to their network drive.

Enjoy! 


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