Microsoft is investigating an issue causing this month's KB5082063 security update to fail to install on some Windows Server 2025 systems.

On affected systems, users are also reporting seeing 0x800F0983 install errors when trying to deploy the April 2026 cumulative updates.

"Microsoft is monitoring diagnostic data reports on update installation failures and has observed a recurring error on Windows Server 2025 devices when installing the April 2026 Windows security update (the Originating KBs listed above), released on April 14, 2026," the company says in a service alert spotted by Microsoft MVP Susan Bradley.

"A limited number of affected servers might experience an installation failure accompanied by the error code 800F0983."

Microsoft says it's currently looking into this known issue and will share more details as it learns more about the root cause.

​On Wednesday, Microsoft also warned IT administrators that some Windows Server 2025 devices will boot into BitLocker recovery after deploying the KB5082063 Windows security update, prompting users to enter a BitLocker key.

However, as the company further explained, this is unlikely to affect home users, as affected configurations are typically found on systems managed by enterprise teams.

This week, Microsoft also finally addressed a bug that has been plaguing Windows servers for 1.5 years, causing systems running Windows Server 2019 and 2022 to upgrade to Windows Server 2025 "unexpectedly."

While it initially blamed the issue on misconfigured third-party update management software, Microsoft said it had addressed the issue and that customers can once again check for updates through the Windows Settings app.

Since the start of the year, it has also released several emergency updates to resolve security vulnerabilities in the Routing and Remote Access Service (RRAS) management tool, a Bluetooth device visibility bug, broken sign-ins with Microsoft accounts, and update installation issues affecting the March 2026 non-security preview update.