How to fix Error 85 on Windows 11

by

Troubleshooting Guide: Error 85 – “The Local Device Name Is Already in Use”

Why This Error Happens

Error 85 occurs when Windows 11 attempts to map a network drive or resource to a drive letter or device name that is already assigned to another active connection, whether visible or “phantom” (a stale session that wasn’t properly disconnected). This commonly happens due to leftover cached credentials in Windows Credential Manager, orphaned SMB/network sessions, or a script/batch file attempting to reuse a drive letter without first releasing it. It can also occur if a drive letter is reserved by a disconnected network share that Windows still considers “in use” in the background.

Step-by-Step Resolution Guide

  1. Disconnect the existing mapped drive via Command Prompt
    Open Command Prompt as Administrator and run:
   net use * /delete /y

This forcibly removes all existing network drive mappings, clearing phantom connections.

  1. Check for a specific conflicting drive letter
    If you know which letter is causing the conflict (e.g., Z:), run:
   net use Z: /delete

Then attempt to remap the drive using:

   net use Z: \\ServerName\ShareName
  1. Clear stored credentials in Credential Manager
    Navigate to:
   Control Panel > User Accounts > Credential Manager > Windows Credentials

Look for any entries related to the server/share causing the issue and select Remove. Restart the mapping attempt afterward.

  1. Restart the Workstation and Server services
    In an elevated Command Prompt, run:
   net stop workstation
   net stop server
   net start workstation
   net start server

This resets the SMB client/server session state without requiring a full reboot.

  1. Reboot the machine if issues persist
    If the drive letter conflict continues, restart Windows 11 entirely to clear any lingering handles or cached network sessions that survived the service restart.

Alternative or Verification Steps

  • Verify the fix: Run net use in Command Prompt to confirm no duplicate or stale mappings exist, then attempt to remap the drive to ensure it connects without Error 85.
  • Alternative solution: If the same drive letter keeps failing, map the share to a different, unused drive letter (e.g., Y: instead of Z:) as a temporary workaround while you investigate what process is holding the original letter.