We recommend that you use an account that has limited permissions for the Unattended Service account. Some external data provider connection strings may contain attributes that try to create temporary files on the computer that is hosting the external database. For example, the attributes may try to create temporary cube (.cub) files. Additionally, any workbook that is uploaded to a computer that is running Excel Services may be able to connect to a data source for which the unattended account has Read permissions.
Some examples of external data providers are as follows:
- Microsoft SQL Server OLE DB driver (OLE DB)
- Microsoft SQL Server ODBC driver (ODBC)
- Microsoft OLE DB Provider for OLAP Services (MSOLAP)
To configure the Excel Services Unattended Service account, follow these steps:
- Click Start, point to Administrative Tools, and then click SharePoint 3.0 Central Administration.
- On the Central Administration page, click Shared Services Administration.
- On the Manage this Farm's Shared Services page, click the default shared services provider that you want to change.
- On the Shared Services Administration page, click Edit Excel Services Settings under Excel Services Settings.
- Next to External Data, enter the Unattended Service account information. Make sure that you use an account that has limited Write permissions.
Note This step lets the account access the required data. Additionally, this step helps prevent the account from accessing critical data or sensitive data. This step also prevents temporary files from being created on the computer that is hosting the external database.