I am receiving the following error when I try to process
any dimensions or cubes in Analysis Services:

Data source provide error: Login failed for user 'NT
Authority\System'

However, I am able to test the data source connection
successfully and edit the cube.

Any ideas on how to solve this processing problem?

Thanks in advance.

Hi,

Are the SQL Server and the Analysis Services in the Same
machine?

Check whether the account in which MSSQLServerOLAPService
is running has got enough rights to connect to the SQL
Database.

When you test the connection from the Analysis Manager, it
takes in the Windows logged in users' credentials to check
the database connection. But when we process the cubes, it
takes in the User credentials of the
MSSQLServerOLAPService account to connect to the SQL
Database.

HTH.
Cheers,
Sanka