I got a notification that this update had downloaded itself and was waiting installation, which I allowed it to do. It took an inordinate time to install and after restarting a couple of times I got the message that it cannot be installed and was undoing all the changes. This happened a couple of times. So, I downloaded and ran the Windows Update Troubleshooter, which listed two errors which it also fixed. Tried the download again, again it failed. Any ideas as to what is going on? And, as a reference, the same update installed on my SP4 - though it took a very long time. But it installed just fine. Thanks in advance.