Windows 11 KB5029263 update is experiencing installation failures on numerous systems, and users have also claimed that the security patch has disrupted the new ‘Microsoft Defender’ app. KB5029263 is the Patch Tuesday update for August 2023 and it resolves one of the most frustrating bugs that affected the performance of SSDs on various devices.

Microsoft released KB5029263 on August 8 to all devices outside the company’s testing program. As previously mentioned, the August 2023 update for Windows 11 addresses the SSD bug and resolves an issue that impacted specific display and audio devices. Additionally, the patch addresses problems with widgets and virtual private networks (VPN).

The update is a mandatory security patch that is intended to download and install automatically. However, some users are receiving notifications from Windows Update indicating that the update failed to install.

The August 2023 update is failing to install for many users. It has been observed by our readers, as well as users in the Feedback Hub, that the Windows 11 KB5029263 (August 9) update cannot be installed and dismissed. One user mentioned that they have a persistent “red dot warning on the taskbar that will not go away.”

Another user reported that the cumulative update process is stuck at 96% on their system, and even after a reboot, the process starts again and gets stuck once more. Some users have also encountered issues with File Explorer, where explorer.exe freezes. A user explained in a Feedback Hub post that after the installation of patches KB5029263 and KB5028948 on August 12, 2023, their system was unable to open any folder or file. Although the application loaded, it failed to function.

Reports have also emerged regarding the Microsoft Defender app, which is failing to launch with an error message stating “Unable to log into Microsoft Defender.” It is not clear how a cumulative update has impacted Defender, but it is possible that it is related to the security fixes included in the patch.

Furthermore, it has been reported that Microsoft’s Surface Pro X is experiencing issues with this update, as some users are unable to access the Snapdragon X24 LTE modem. In the Device Manager, users see an error message that states “The device cannot start. (Code 10)” when they select the LTE modem label.

Unfortunately, attempting to reinstall drivers and refresh drivers with the ones provided on the Microsoft website does not resolve the problem caused by the update for Surface Pro X owners.

At present, Microsoft has not yet acknowledged these reported issues.