KB5066791 Windows update failed to install

Nikolai Malakhov 5 Reputation points
2025-10-31T23:41:16.53+00:00

Trying to update my Windows. I had a few updates pending so I decided to update the system, everything installed perfectly except KB5066791 Security update. I have tried different ways to install the update but nothing works. I have tried safe mode install. manual install nothing works. Those 2 error codes are the most common 0x80071a2d 0x800f0923. Please help!

Windows for home | Windows 10 | Windows update
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  1. John DeV 153.1K Reputation points Independent Advisor
    2025-11-01T01:42:24.1233333+00:00

    Please let me know if you have tried the method below.

    • Install the KB5066791 update again.
    • Once you see the orange dot on the power icon, Hold Left Shift + Left Click on Restart. (not “Update and Restart”)
    • Once it boots into WinRE, go through the menus to boot into Safe Mode.
    • Once you’re in Safe Mode, just restart normally.

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