At times, end users attached to CIFS shares may experience issues with authenticating or connecting to shares. Increasing the debug level on a per user/computer basis helps to isolate potential issues that may not be evident with the default logging level of the samba logs.
This article describes the procedure to increase Samba related logging levels, including the level of detail captured and the log file size. By limiting the elevated logging to only the machine being investigated, the increased resource utilization can be minimized (High logging levels carry a heavy IO and CPU burden.) The procedure outline here will allow you to target elevated logging to an individual client machine.