I am experieriencing similar behavior on a Windows 7 x64 machine as this KB 943451 - whereby when accessing an MCP share I cannot get connected.The shares are on \\MCPServer - trying to browse - I get diagnose problem errorA direct share \\MCPServer\MCPShare - trying to browse - I get same diagnose problem errorMapping the drive as Z: using other credencials - keyed in as all caps even in quotes as indicated in this post on another forum - did not work for me - I get bad username / password http://social.technet.microsoft.com/Forums/en/winserverfiles/thread/1f1405d6-ab88-484e-a103-71b7b45f6b61 LM or NTLM - negociate NTLMv2 if requested is enforced policy - I believe that when I was in Vista world prior to upgrading to Win7 this was actually the solution.Nothing in event viewer.Stumped. - Please help.J