Unattended Execution Account in SSRS

Question

Q1: why would I want to have an Unattended Execution Account?

Q2: if I don\'t use an Unattended Execution Account, which account is used to run the reports?

Q3:

Answer 1

The MSDN article has pretty detailed information about this.

From that the answers to your questions are:

Q1: You should set the Unattended Execution Account if you don't want to set credentials for data sources and want the data source to work even when users are not able to enter their credentials (subscriptions or other scheduled executions.) From the linked MSDN article:

The unattended report processing account is used primarily to connect to external servers, and not as a login to database servers. If you want to use the account credentials to log in to a database, you must specify credentials in the connection string. You can specify Integrated Security=SSPI if the database server supports Windows integrated security and the account used for unattended report processing has permission to read the database.

Most SSRS installations do not need the Unattended Execution Account. They use the "Credentials stored securely in the report server" option in the data sources.

Q2: I'm not sure what "run the reports" means, but the SSRS Service account is always responsible for the rendering and delivery of the reports, whether an Unattended Exec Account is set or not. The connections to the data sources will use the credentials specified in the data source. Unattended Exec Account will only be used if the data source is set to "Credentials are not required."

Q3: This account may not be used at all, but SSRS still checks the credentials with the domain. If none of your data sources are set to "Credentials are not required" then I recommend you remove the account from the SSRS configuration.