I agree, George. For me this only happens on the computers that are not joined to the domain (Workgroup computers). When the issue occurs for us I usually do a repair (right click the network connection and select repair, or in Vista "Diagnose and Repair") on the connection and delete the Network Place associated with the AC share and then remake the share giving credentials when asked. The problem seems to be with credential loss, not just to the SQL server but to the share. I can still seemingly access the share when the problem happens but I believe what I see is some sort of "cached" folder contents. When I browse to the AC database through the share I get the error again. This problem started happening either at the end of last year or the beginning of this year for us, but we were on V4 during beta since last Fall.
