S-User in Maintenance Optimizer 
Your S-user is the user ID which SAP gave you, to logon to the SAP Support Portal.
Note
Always logon to the SAP Support Portal with your S-user, to which your SAP Solution Manager user ID is assigned. The Maintenance Optimizer can only confirm and authorize files which you put in the download basket for this S-user.
Your system administration has assigned an S-User for the SAP Support Portal to you. Use the transaction AISUSER, or, in Customizing for SAP Solution Manager, choose the corresponding activity under .
Note
Your S-user must be assigned to the same customer or company number as the S-user which your system administration put in the destination SAP-OSS RFC. Otherwise, the Maintenance Optimizer cannot read your download basket.
The Maintenance Optimizer is connected to the SAP Support Portal of the SAP Global Support Backbone, and provides the following functions:
It takes you directly to the area of the SAP Software Distribution Center for the product that you have selected for maintenance. (Log on with your S-user.)
It reads the download basket of your S-user.
It authorizes selected items in the download basket so that they can be downloaded.
It gets the selected items in the maintenance transaction.