Yesterday my database was connected perfectly.. We have installed Windows Server 2008 R2 on our server and the i have added the user to the client PC name SMTECH5 with user jangid Now my database is not connecting using windows authentication. only the master database is connecting.. here are somw of the error throwned TITLE: Connect to Database Engine Cannot connect to SMTECH5\COLLEGEERP. ADDITIONAL INFORMATION: Cannot open user default database. Login failed. Login failed for user 'SMTECH\jangid'. (Microsoft SQL Server, Error: 4064) For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&EvtSrc=MSSQLServer&EvtID=4064&LinkId=20476 BUTTONS: OK TITLE: Connect to Database Engine Cannot connect to SMTECH5\COLLEGEERP. ADDITIONAL INFORMATION: Cannot open user default database. Login failed. Login failed for user 'SMTECH\jangid'. (Microsoft SQL Server, Error: 4064) For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&EvtSrc=MSSQLServer&EvtID=4064&LinkId=20476 BUTTONS: OK this happens on all the pcs in our lab