The MSSQLServerOLAPService service account must also have logon account permissions to access the source data in the source database if trusted connections are used to access the source data. With trusted connections, the MSSQLServerOLAPService service account is used to connect to the data source. If trusted connections are not used, you can specify a user name and password. The permissions required when connecting to a data source also depends on the type of storage structure used for the Analysis Services partitions. When MOLAP storage is used, the service account must have at least SELECT permissions on the source database. If ROLAP or HOLAP storage is used, the service account must have at least SELECT and CREATE TABLE permissions on the source database.