The Windows security updates that Microsoft distributed for the October Patch Day can cause the Bitlocker recovery to start when the computer is restarted. The boot process can then only be completed by entering the recovery key.
Microsoft did not publicly admit this in the Windows Release Health notices but instead hid it in an entry accessible only to paying administrators in the Microsoft Admin Center. The manufacturer writes: “After installing the Windows updates released on or after October 14, 2025 (KB5066835), some devices may experience issues wi…
The Windows security updates that Microsoft distributed for the October Patch Day can cause the Bitlocker recovery to start when the computer is restarted. The boot process can then only be completed by entering the recovery key.
Microsoft did not publicly admit this in the Windows Release Health notices but instead hid it in an entry accessible only to paying administrators in the Microsoft Admin Center. The manufacturer writes: “After installing the Windows updates released on or after October 14, 2025 (KB5066835), some devices may experience issues with restarting or booting. Affected devices may start with the BitLocker recovery screen, requiring users to enter the recovery key once. After entering the key and restarting the device, it will boot normally without further BitLocker prompts.”
Partial uninstallation provides a remedy
The company further explains: “The problem appears to primarily affect Intel-based devices that support Connected Standby – a feature that allows devices to remain connected to the network even in a power-saving mode.” To resolve the issue, Microsoft offers a Known Issues Rollback (KIR), which is a partial uninstallation of the Windows updates. Administrators who wish to implement this in their setup should contact Microsoft Support.
According to Microsoft, all supported client operating systems are impacted: Windows 10 22H2, Windows 11 22H2, 23H2, 24H2, and 25H2. Servers apparently show no such problems. Microsoft states that it is still investigating the issue.
If you use Windows, you should ensure that you have a copy of the Bitlocker recovery key accessible or stored in your Microsoft account. Bitlocker is often activated in Windows Home versions without users having created a backup. In such situations, affected individuals run the risk of losing access to their data on the computer.
In October, there were already further undesired side effects of the security updates and update previews for Windows. Microsoft reported failed authentication with smart cards, non-functional mouse and keyboard in the Windows recovery environment, or failure to load IIS websites from localhost.
(dmk)
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This article was originally published in German. It was translated with technical assistance and editorially reviewed before publication.