In version 9.1 or older you sometimes will encounter one of the following errors.... "error (handshake failed), error (Patch List Download Failed)". This issues are sometimes easily resolved by deleting the ospx and checksuns in affected machines (located at Programfles x86\quest\kace).
A guy from support provided me the following scripts so you can do that from the KSMA massively
Here you can download them
Then you just need to import them as this KB shows How to import and export resources (116949)
Hope it works for you as much as it have been working for me :-)