The update is not applicable to my computer.
There were problems downloading some updates, but we'll try again later. If you keep seeing this, try searching the web or contacting support for help. This error code might help: (0x800f0805)
KB5122878 Failed to install on 9/10/2026 - 0x800f0805
Windows for home | Windows 10 | Windows update
4 answers
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SD - IA 178.7K Reputation points Independent Advisor
2026-09-10T15:02:04.76+00:00 Hello,
That means it is either installed or you are not running 64 bit machine.
Please supply the following Information.
Right-click the Start button and Choose the Run option
Type in msinfo32
Press enter.
Take a screenshot of the System Summary window and post it in the next reply.
I look forward to your response and am eager to collaborate until we find a solution.
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Eugene Co 0 Reputation points
2026-09-10T10:55:06.3+00:00 The update is not applicable to my computer.
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SD - IA 178.7K Reputation points Independent Advisor
2026-09-10T08:36:09.4166667+00:00 Hi,
I will walk through a few steps with you. Some of these are just to help figure out what is wrong, not to fix it right away. So if nothing changes after a step, that is normal. I will keep going until we solve it.
Download the offline package from https://catalog.s.download.windowsupdate.com/d/msdownload/update/software/secu/2026/09/windows10.0-kb5122878-x64_191c536a44656eb754daa7cb7e9b517b05d690f7.msu and try installing it. Let me know if it installs.
I look forward to hearing from you to get the results of the troubleshooting.