Now that we have discussed the crucial causes, let’s explore the solutions to this issue.
1. Reset the Windows Update Component
As stated earlier, the error can be caused by a problem with Windows Update components, such as Windows Update services or files downloaded via the Windows Update utility. By resetting the Windows Update component, you not only restart the stopped Windows Update services but also clear the SoftwareDistribution folder that might contain corrupted files, resulting in this issue.
2. Perform an In-place Upgrade
An in-place upgrade involves downloading a Windows ISO file and running it by mounting the file. This process replaces any corrupted components and updates Windows to the latest version. It is highly recommended to perform an in-place upgrade if the issue persists.
3. Download the Windows Update Manually
We can also manually download a Windows update if it fails to install due to issues with the Windows Update component or other reasons. Downloading the Windows update manually is one of the straightforward ways to resolve any Windows update error.
4. Run SFC and DISM Commands
Running the SFC (System File Checker) and DISM commands can help resolve the error 0x800f0991 by repairing corrupted files. SFC is a command-line utility that repairs system files, including DLL and executable files. Meanwhile, DISM goes a step further and fixes deeper issues within the system, including the Windows Update component. Windows update errors can also occur due to insufficient space on the system drive. By performing a disk cleanup, you not only remove corrupted temporary and cache files but also free up space for the upcoming Windows updates. So if you don’t have enough space, you can try running the disk cleanup utility by following the steps in the linked article.
