When you map a network drive to a local share, your System event log receives:

Event ID: 3019                              Source: MRxSmb                              Description: The redirector failed to determine the connection type.
This error is known to occur with TCP/IP over a Loopback adapter. The Loopback adapter does not handle speed negotiation.

You can safetly ignore this event.

The event occurs:

1. On the first access after you log on.

2. On the first access after resuming from hibernation mode.

3. On the first access after an autodisconnect. Turn off autodisconnect.

NOTE: See When a program running on Windws XP SP2 connects to an IP address in the loopback range, it may not work as expected?