Loading story…
Microsoft released a second January out-of-band Windows update, KB5078127, to remediate issues introduced by the January Patch Tuesday security update (KB5074109) that disrupted cloud-backed workflows on Windows 11. Reported impacts included applications being unable to open or save files to cloud storage providers such as OneDrive and Dropbox, with a common enterprise failure mode involving Outlook hanging when PST files were stored on OneDrive; users often had to terminate processes or reboot to recover.
KB5078127 is a cumulative OOB release that rolls up prior January fixes, including the earlier out-of-band update (KB5077744) and the security/quality improvements from KB5074109, and it also includes a bundled Servicing Stack Update (KB5071142) intended to improve update reliability. The update is available via Windows Update and the Microsoft Update Catalog; organizations with automatic updates enabled should receive it automatically, while IT teams can expedite deployment through standard Windows update management workflows.
Mallory correlates global threat intelligence with your attack surface — know if you’re exposed before adversaries strike.
4 events from the most recent confirmed update back to the earliest known activity.
On January 26, 2026, Microsoft released out-of-band cumulative update KB5078127 to fix file system compatibility bugs introduced by KB5074109. The update addressed application freezes, cloud storage failures involving OneDrive and Dropbox, and Outlook hangs when PST files were stored on OneDrive, while also including prior January security and quality fixes.
By January 26, 2026, Microsoft was investigating another issue linked to the January Windows updates that could leave some Windows 11 24H2 and 25H2 systems unable to boot, showing a black screen and an UNMOUNTABLE_BOOT_VOLUME stop code. Affected devices could require manual recovery through Windows Recovery.
On January 17, 2026, Microsoft issued an out-of-band update, KB5077744, to address problems with remote connections to Windows Cloud devices and Secure Launch. This fix was later bundled into a subsequent emergency update.
On January 13, 2026, Microsoft released security update KB5074109 for Windows 11. The update later proved to introduce file system compatibility problems affecting cloud storage workflows and Outlook PST files stored on OneDrive.
Vulnerabilities, threat actors, malware, products, organizations, and breaches Mallory has linked to this story.
3 references tracked. Mallory keeps watching after this page renders.
zdnet.com
Open sourcecybersecuritynews.com
Open sourcecsoonline.com
Open sourceMap indicators from this story to your assets and identify affected systems in minutes.
Every observed campaign, victim, and pivot linked to actors named in this story.
Malware, exploits, and IOCs connected to the activity described here.
YARA, Sigma, and Snort rules deployed to your SIEM as soon as they’re published.
Get matching new stories delivered to your team as they break — not the next morning.
Ask questions about this story and take action on the answers.
Other stories Mallory is tracking that overlap on entities, sources, or topic labels.
Microsoft’s January 2026 Patch Tuesday release for Windows 11 (notably **KB5074109** for 24H2/25H2) delivered roughly 100+ security fixes (including reported **zero-days**) but also introduced significant reliability regressions. Reported impacts include **system lockups**, **black screens** on systems with Nvidia/AMD GPUs, graphics-related hangs in GPU/DirectX-intensive applications, and application failures such as **Outlook Classic** freezing or failing to launch; additional issues were reported with File Explorer behavior and cloud-backed storage workflows (e.g., OneDrive/Dropbox) causing apps to become unresponsive when saving or syncing data.
Jun 29, 2026
Microsoft reported a service incident impacting **Microsoft 365** core services, with users experiencing connectivity issues and service degradation across **Exchange Online**, **Microsoft Teams**, and the broader M365 suite. The incident was tracked as `MO1220495`, with Microsoft stating it was still in the *investigating/diagnostic* phase and providing no estimated time to resolution; organizations were directed to monitor the Microsoft 365 Service Health Dashboard for tenant-specific impact details. Separately, Microsoft published guidance for a client-side stability issue where the classic **Outlook desktop** app can freeze/hang after installing recent Windows security updates (notably `KB5074109`, and also `KB5073724`), particularly affecting POP accounts and scenarios where Outlook `PST` files are stored on cloud-backed storage such as **OneDrive**. Recommended mitigations included using webmail, moving `PST` files off OneDrive, or uninstalling the problematic updates while Microsoft investigates. A third item describing “Microsoft data breach” and “zero-day vulnerabilities” is largely a repackaged Patch Tuesday/vulnerability roundup and does not substantively align with the M365 service incident or the Outlook-freeze regression.
Jun 29, 2026
Microsoft released the mandatory Windows 11 cumulative update **KB5101650** for versions **25H2** and **24H2**, alongside **KB5099414** for **23H2**, as part of its latest Patch Tuesday rollout. The update advances Windows 11 builds to **26200.8875** and **26100.8875** for 25H2 and 24H2 and includes fixes for **571 vulnerabilities**, with security-critical items such as continued **Secure Boot** certificate deployment delivered in the normal rollout phase. Microsoft said 25H2 and 24H2 receive the same package because both are based on 24H2, and no new known issues were acknowledged for the release. Beyond security fixes, KB5101650 adds and expands several user-facing and reliability improvements, including broader availability of **Point-in-time restore**, the new accessibility feature **Screen Tint**, quieter **Widgets**, and more flexible update pausing. Microsoft also addressed Bluetooth pairing and audio issues, including improvements for AirPods and call handling, while fixing problems affecting **File Explorer** performance, `explorer.exe` stability, Recycle Bin file naming, taskbar badges, networking in virtualized environments, **WSL** VPN connectivity, printing, **BITS** shutdown delays, and GIF support in the emoji panel after a switch from Tenor to **GIPHY**. The update is being distributed automatically through Windows Update and is also available as an offline `.msu` installer through the Microsoft Update Catalog.
Jul 17, 2026