Windows cannot access Mac share after upgrading to El Capitan (OS X 10.11)

After upgrading to OS X El Capitan (from Mavericks) we were no longer able to access a shared folder from any Windows machine.  It would error saying ‘The specified network password is not correct’.

el_capitan_shared_folder_access_01

The resolution was to change the network logon authentication mode on the Windows machine.  We changed it from Send LM & NTLM – use NTLMv2 session security if negotiated to Send NTLMv2 response only.  This immediately resolved the access issue to the shared folder.  You can configure this setting using any of the following methods.

Registry

  1. From the Run command type in Regedit and click Ok.
  2. Navigate to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\LSA
  3. Modify lmcompatibilitylevel and set value to 3.
    Note: This value can be set from 0-5, click here to see the setting for each value.
  4. Exit the registry editor.
    el_capitan_shared_folder_access_02
    If you are familiar with the Reg add command, you can complete the above steps in one line.
    REG ADD “HKLM\System\CurrentControlSet\Control\Lsa” /v “lmcompatibilitylevel” /d 3 /t  REG_DWORD /f

Local Security Policy

  1. From the Run command type secpol.msc and click Ok.  This will open the Local Security Policy Editor.
  2. Navigate to Local Policies\Security Options.
  3. Modify the policy, Network security: LAN Manager authentication level.
  4. Change the setting to Send NTLMv2 response only and click Ok.
    el_capitan_shared_folder_access_03
  5. Exit the Local Security Policy Editor.

Group Policy

  1. Open Group Policy Management.
  2. Create a new GPO (or modify an existing one).
  3. Navigate to Computer Configuration\Policies\Windows Settings\Security Settings\Local Policies\Security Options.
  4. Modify the policy, Network security: LAN Manager authentication level.
  5. Change the setting to Send NTLMv2 response only and click Ok.
    el_capitan_shared_folder_access_04
  • December 17, 2015 - 3:30 pm

    skip - great info! Thanks,this worked for me, even though I had upgraded from Yosemite (not Mavericks) to El Capitan.ReplyCancel

    • December 17, 2015 - 3:33 pm

      Todd - At your service!ReplyCancel

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