Error: Failed to retreive data for this request. An exception occured while executing a Transact-SQL statement or batch. The server principal "username" is not able to access the database "databasename" under the current security context.

Resolution:
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.