If this error message appears when trying to expand the databases node in SQL Server Management Studio and the x64 version of SQL Server 2008 is installed, follow the steps below:
1) Bring Object Explorer Details window by selecting View –> Object Explorer Details in menu (or hitting F7)
2) In Object Explorer window click at Databases folder
3) In Object Explorer Details window right-click at the column header and deselect Collation
4) Refresh Databases folder.
For more details click here.