Dieses Verhalten könnte durch
KB3020369 ([wahrscheinlich] Voraussetzung für KB3172605) verursacht werden:
KB3020369 wrote:Known issues for this update
Restart stuck on "Stage 3 of 3"
After you install update 3020369 together with other updates, a restart may be required to complete the installation. During this restart, you may find yourself stuck on "Stage 3 of 3."
If you encounter this issue, press Ctrl+Alt+Delete to continue to log on. This should occur only one time and does not prevent updates from installing successfully.
An update installation fails after you install update 3020369
When you install update 3020369 together with other updates, you may encounter a timing issue that causes the update tried immediately after you install update 3020369 to fail.
This issue only affects the update tried immediately after update 3020369. As soon as update 3020369 is installed, another try to install the failed update should be successful.
Note In managed environments, such as by using Windows Server Update Services (WSUS), you can avoid either of these issues by deploying this update as a stand-alone update.
Vielleicht sollte DoUpdate.cmd KB3020369 einzeln installieren, was aber einen zusätzlichen Neustart mit sich bringt.