An outlook client was connected to Exchange 2010 when the power cord to the client machine was pulled. Now the client gets an error "Unable to open your default e-mail folders. The Microsoft Exchange Server computer is not available. Either there are network problems or the Microsoft Exchange Server computer is down for maintenance. (/0=......). Neither of the above conditions exist. The client can ping the Exchange server and can access all network resources. I deleted and recreated the user's mail profile. I also cannot connect to the mailbox from any other machine via outlook. I am able to create a mail profile for another active mailbox on this client machine and it connects ok. I am able to access the errant mailbox via OWA. It appears that the mailbox on the Exchange server has somehow disabled MAPI access. I checked the mailbox properties and disabled and then re enabled the MAPI protocol, still not good. Cache mode is disabled on the client.