Troubleshooting Update problems
In our experience, Windows Update is generally reliable, but problems can and do occur. These problems fall into a handful of categories: updates that cause stability problems; updates that fail to install properly; and general problems with Windows Update.
For updates that cause problems, the first step is to remove the offending update. (For particularly nettlesome problems, this might require booting into Safe Mode.) Go to Settings → Update & Security → Windows Update. Click View Update History to display the list of installed updates and then click the unobtrusive Uninstall Updates link at the top of that page.
Doing so takes you back to the old-style Control Panel, where you'll find an inventory of everything that Windows Update has installed for Windows itself and for other Microsoft products, as well as a smattering of updates for third-party products that register those updates with Windows. From this page, you can confirm that a particular update has been installed by referring to its KB number in the list of installed items. Some items may include a support link at the bottom of the page-this leads you to details about the selected update. The Uninstall option appears above the list when you select an update. Click that option to remove the update, but do so only as a last resort, and only when your troubleshooting leads you to suspect that a recently installed update is causing serious performance or reliability issues.
That action (after a restart) removes the immediate problem. But because of the way Windows Update works, the unwanted item will reappear the next time Windows checks for updates. You can interrupt this cycle by "hiding" the offending update.
To do this, you need to run the Show Or Hide Updates troubleshooter package, which you can download from https://support.microsoft.com/kb/3073930. The troubleshooter presents a list of updates that can be hidden. Select the item that you don't want to reinstall. The ruse is temporary, but it should give you respite until a revised update becomes available.
Troubleshooting Windows Update is stuck in a reboot loop
In some cases, Windows Update can get stuck in a loop, failing to complete the installation of one or more updates and continually repeating the unsuccessful update process each time you restart.
Reset Windows Update completely, removing content from the update cache and starting with fresh downloads. In most cases, that's enough to get things unstuck.
Microsoft created a help resource for diagnosing and fixing Windows Update problems, which is available at https://support.microsoft.com/kb/971058. The process involves stopping several services, removing the folder containing updates in progress, and reregistering a list of system files. You can download a troubleshooter that performs these steps automatically from https://aka.ms/wudiag.