OS X Lion: Connecting to older SMB servers that do not support UNICODE or NT style commands

Learn how to connect OS X Lion to older SMB servers that do not support UNICODE or NT style commands. This includes Microsoft Windows 98 and some Network Attached Storage (NAS) devices that use the Windows 98 version of the SMB protocol.

You can determine if you are trying to connect to a device that only supports the earlier protocol by looking for a message such as this in the system.log:

"smb_smb_negotiate: Support for the server SERVER_NAME has been deprecated (PreXP), disconnecting"

To enable OS X Lion to connect to this device, execute the following Terminal command:

sudo sysctl -w net.smb.fs.kern_deprecatePreXPServers=0

This change will be in effect until the OS X Lion computer is restarted.

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To revert the setting back without restarting, you can execute this Terminal command:

sudo sysctl -w net.smb.fs.kern_deprecatePreXPServers=1