Problems caused by the February 9 update forced Microsoft to rush out KB5001078 to fix them

Article published in February 2021. Microsoft fixed the problem shortly afterward; at the end, you’ll find what still applies in 2026.

On February 12, 2021, Microsoft released KB5001078, a new servicing stack update for Windows 10 version 1607 and Windows Server 2016, after KB4601392, the update released on February 9, had caused users a lot of headaches.

The KB4601392 update had a bug: once it was installed, that month’s cumulative update would get stuck at 24% and stay there. Microsoft pulled it and released KB5001078, which fixed the errors of the previous one.

According to Threatpost, Microsoft recommended the following steps at the time for computers that had already installed KB4601392:

• restart the workstation and follow steps 1, 2 and 4a of the manual procedure for resetting the Windows Update components;
• after making these settings, restart the operating system again;
• run “Check for Updates,” and the KB5001078 update would install correctly.

The full instructions are on Microsoft’s page about manually resetting the Windows Update components. Steps 1, 2 and 4a there open the command prompt, stop the services used by Windows Update and rename the folders where Windows keeps downloaded updates (SoftwareDistribution and catroot2).

On computers that hadn’t installed the faulty update yet, KB5001078 was downloaded and installed automatically through Windows Update. The official details are on the KB5001078 update page on Microsoft’s website.

How should a company prepare for situations like this?

With a recent backup and with updates installed in stages, not on all computers at once. Specifically, your company should:

• have an effective backup policy to fall back on if an update breaks something;
• not rush to install system updates as soon as they come out, except for those that fix vulnerabilities already being exploited by attackers;
• install updates in stages: first on a few test computers, then on the rest;
• not start the round of updates with the company’s critical workstations and servers, so that problems don’t hit important systems;
• do some research before installing updates, on specialist forums and on the Windows release health page, where Microsoft announces known issues.

Problems like these can create very complicated situations for a company and should be avoided. KB4601392 wasn’t the only troublesome update: in 2020, after another update, workstations could no longer print, and another time a security update broke search in the email client.

Does this problem still matter in 2026?

No: the problem was solved long ago, and Microsoft pulled KB4601392 back in February 2021. In the meantime, the affected systems have also reached the end of their lives. Windows 10 Enterprise LTSB 2016, the last edition of Windows 10 based on version 1607, went out of support on October 13, 2026, and Windows Server 2016 receives security updates only until January 12, 2027. Computers and servers still running them need to move to Windows 11 and to Windows Server 2022 or 2025, respectively. We explain why this matters in the article on end-of-life technologies.

The lesson still holds, though: any update can break something, so updates should be tested, installed in stages and applied only when you have a recent backup.

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