You may have clients that have already downloaded one or more updates that were signed with the old certificate. In this situation you must clear the old updates from the clients’ cache so that the newly-signed updates can be downloaded by the client.
1.On each client, use Control Panel to locate and open the Configuration Manager Properties dialog.
2.On the Cache tab, click Configure Settings.
3.Click Delete Files.
4.Enable the Delete persisted cache contents check box.
5.Click Yes and then OK.