Admin: 'I spent all weekend on my servers' after Microsoft breaks Exchange Server with October updates

Microsoft has acknowledged that the October 2026 Windows Server updates may be destabilizing Exchange Server. The problems are related to this list of Windows Server updates (see here) and Microsoft makes it clear they are not related to the October 2026 security updates for Exchange Server. The software giant says the bug can hit Exchange Servers running Windows Server 2016, 2019, 2022, and 2025.