KB5085516: Emergency Update Fixes Microsoft Account Sign-In Broken by March Patch Tuesday
Summary: Microsoft released an emergency out-of-band update, KB5085516, on March 21, 2026, to fix a sign-in breakage introduced by the March Patch Tuesday cumulative update KB5079473. The bug caused Microsoft account sign-ins to fail across Teams, OneDrive, Edge, Excel, Word, and Microsoft 365 Copilot — even on devices with a working internet connection.
What happened: After installing KB5079473 (released March 10, 2026 as part of Patch Tuesday), affected Windows 11 devices entered a broken network connectivity state that caused any Microsoft account authentication attempt to fail with the misleading error: “You’ll need the Internet for this. It doesn’t look like you’re connected to the Internet.”