We’ve seen connectivity issues with both Macintosh and Windows Navigator Clients (dropping shares, disconnecting, etc.) that were resolved by making a change to a Registry Key on Windows 10 Pro.  We also have seen Mac client connectivity improved with a local security policy change and a sharing change.


There are two changes you could make.  The first is general and applies to Windows or Mac clients.  The second is specific to Mac clients.

1. Large System Cache (Regedit change)

  • Close any open software (especially Navigator) and launch Regedit.    To launch, type regedit’ in the Windows Start menu, double-click regedit.exe to open it. 
  • Set the following registry key to ‘1′ : 

HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\LargeSystemCache

Double-Click ‘LargeSystemCache’ to make the change, Enter 1, Click ‘Ok’ to close.


2.  Mac client connectivity to Windows (Local Security Policy and sharing changes)

  • On the Windows (Navigator) platform, go to:

Start Menu>type in "local" to get to the setting, double-click "Local Security Policy" to open

    Local Policies

        Security Options

Network Security: LAN Manager authentication level

                           Double-Click to Open,  

  • Change to Send LM and NTLM Responses.     
  • Click OK and then exit.



  • Go to the Windows Start menu - type in Features
  • Double-Click to Open 'Turn Windows Features On or Off'
  • Locate SMB 1.0/CIFS File Sharing Support and enable all three entries as seen below:





  • Click Ok and exit.
  • Reboot the PC for the changes to become effective.