kb5078127

Outlook crashing on Windows 11 after January’s Patch Tuesday left inboxes frozen, mailboxes mismatched, and IT teams scrambling — and Microsoft’s emergency out-of-band update finally appears to have stopped the worst of it. The fix targets a flaw introduced by the January 13, 2026 security...

A routine January Patch Tuesday rollup (KB5074109) accidentally left parts of Microsoft’s classic Outlook experience unstable for a measurable number of users, triggering freezes, lingering OUTLOOK.EXE processes, lost Sent Items and a rapid sequence of follow‑up fixes and mitigations from...

Microsoft’s emergency out‑of‑band update KB5078127 is a targeted, cumulative patch for Windows 11 that consolidates the mid‑January fixes and corrects a high‑impact file I/O regression that left Outlook and other apps hanging when they tried to open or save files in cloud‑synced folders such as...

Microsoft released an out‑of‑band cumulative update for Windows 11, version 23H2—KB5078132 (OS Build 22631.6495)—on January 24, 2026 to address a set of post‑Patch‑Tuesday regressions and to roll together prior January fixes into a single package for affected systems. The package is explicitly...

Microsoft has released an out-of-band cumulative update, KB5078127 (OS Builds 26200.7628 and 26100.7628), to address a series of January 2026 quality problems — and it includes a mitigation for a persistent, user-facing regression theat first appeared after the August 29, 2025 non‑security...