Disabled check boxes for exclusions on the Import Patch Data for Windows (PMImport) > Vendors and Software section, enabled the setting 'Delete previously downloaded data for vendors, software and languages that are now excluded' and executed the process as seen here:
Found the process fails with exception errors in log viewer.
Description: Exception occured while executing task c27dbb50-6ddf-4125-87c1-d8f5b588491d. Unable to cast object of type 'Altiris.SoftwareManagement.Resources.SoftwareUpdateResource' to type 'Altiris.PatchManagementCore.Resources.PatchSoftwareUpdateResource'.
Software Management associations, or other resources, have become associated to the Patch Software Release that is being disabled and the process is unable to clean-up the improper associations.
Work through the following to resolve this in the SMP Console:
Import the attached custom SQL report: Improper Associations Linked to Patch Software Release.xml
Go to the Console > Reports > All Reports > Software > Patch Management
Highlight the Patch Management Folder in the left-pane tree
Right-click > Import; select the above named report in the popup and Save
Open the Improper Associations Linked to Patch Software Release Report:
Highlight one single result row
Right-click > Actions > Edit Software Resource
From the opened 'Edit Software Resource' page:
Go to the Associations tab
On the 'Association Type:' dropdown; select 'Updates'
Highlight the row of Name and select the red 'X' to delete the improper resource association
Click 'OK' at the bottom of the page
Repeat steps 1. & 2. as much as needed to clear the improper associations.
Run the PMImport with desired settings when all improper associations have been cleared via the steps above.