When running CRM 2011 SQL based custom report from reporting server we need to specify username and password.
Here username should be systemuserid and password should be organizationid.
If you are using username as domain\account and passport of account, you might get following error.
An error has occurred during report processing (rsProcessingAborted) Cannot create a connection to data source ‘CRM.’ (rsErrorOpeningConnection) Guid should contain 32 digits with 4 dashes (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx).
To get systemuserid and organizationid, you need to run SQL query on CRM database. Here is the query
SELECT fullname, systemuserid, organizationid FROM SystemUser
SELECT fullname, systemuserid, organizationid FROM FilteredSystemUser