In SharePoint 2010, after installation, you will see a warning for unattended service account application Id.

“The Unattended Service Account Application ID is not specified or has an invalid value.”

In order to fix this, you need to create a new secure store target application. Go to Central Administration –>Application Management –>Manager Service Applications –> Secure Store Service –> Generate New Key (in the ribbon) –> Provide the pass phrase (important that you remember this) –> Click on New and provide details (Ensure to select target application type as Group). –> Add/Edit fields for credentials (For now accept the default) –> Provide the Target application administrators and members.

Once target application id is created, go to Go to Central Administration –>Application Management –>Manager Service Applications –> Global Settings –> Provide Application ID created in step 1 here.

Thats it..