Users on Windows 7 started to notice that Windows Defender would not start up anymore for example, and that the Diagnostic Tool of the operating system was not working correctly as well.Some users reported that Windows would not start at all anymore and several other issues such as that the Microsoft Management Console would ask for admin credentials while logged in as an admin or that the installation of Microsoft Security Essentials failed.After ending the update loop, you should fix the root cause.In many cases, at third party system tool like antivirus software is blocking update installation.
Afterward you can try to re-launch the already stopped services.
So uninstall these tools and use a clean tool provided by vendors to remove remaining install files.
If Windows stalls during boot within update installation and you are not able to log into a user account, try the steps given below. Boot your machine into a Windows PE environment (you may boot from a Windows install media an select the option shown in setup wizard, see Windows 10 hangs with error code 0xc0000034). Test, where the drive hosting the Windows installation is, and rename the folder mentioned above within the Windows PE command prompt window.
Options that you have at this point are to boot into Safe Mode if Windows boots still into it, or to use recovery media to run System Restore to undo the update.
This can happen on Windows 7, 8, or 10, but it’s become especially common with Windows 7. No matter what troubles you’re having, we recommend keeping automatic updates turned on—it’s one of the best ways to keep yourself safe from ransomware and other threats.
The troubleshooter works through its process and then lets you know whether it could identify and fix the problem.