- Microsoft released an out-of-band update, KB5078127, to fix bugs introduced by the January 2026 Patch Tuesday update.
- Affected issues include app crashes and Outlook client issues on Windows 11 25H2 and 24H2.
Microsoft is now releasing the Out-of-band (OOB) update KB5078127 as builds 26200.7628 and 26100.7628 for Windows 11 25H2 and 24H2 to address a bug with certain apps and the classic version of Outlook introduced with the January 2026 update.
On January 13, 2026, Microsoft began rolling out the first Patch Tuesday Update of 2026 for versions 25H2 and 24H2, as a small release with only security fixes. However, shortly after, the KB5074109 update for versions 25H2 and 24H2, some users began experiencing sign-in failures during Remote Desktop connections. This bug was also affecting devices running version 23H2.
Although this issue was addressed with the Out-of-band update KB5077744, the company is now rolling out a second Out-of-band update, KB5078127 (builds 26200.7628 and 26100.7628), to resolve apps that might freeze or encounter unexpected errors when opening or saving files stored in cloud services such as OneDrive or Dropbox. In Outlook setups where PST files are kept on OneDrive, the app may stop responding and refuse to reopen until the process is ended or the device is restarted.
In addition, the company released the same fixes for version 23H2 as the January 24, 2026—KB5078132 (OS Build 22631.6495) Out-of-band
update.
Windows 11 25H2 update KB5078127
- Release date: January 24, 2027.
- Builds: 26200.7628 (25H2), 26100.7628 (24H2).
- Purpose: Fixes unresponsive or unexpected errors with some apps and issues with the classic version of Outlook bug introduced with the January 2026, Patch Tuesday update.
- Affected versions: Windows 11 25H2 and 24H2.
Windows 11 23H2 update KB5078132
- Release date: January 24, 2027.
- Builds: 22631.6495 (23H2).
- Purpose: Fixes shutdown and Remote Desktop authentication bugs introduced with the January 2026, Patch Tuesday update.
- Affected versions: Windows 11 23H2.
If you have a computer affected by these bugs, you should install this update immediately by going to Settings > Windows Update and clicking the “Check for updates” button.
Alternatively, you can download and install the update KB5078127 from the Microsoft Update Catalog for Windows 11.
This out-of-band update includes all fixes and improvements from the original January 2026 Security update, released January 13, 2026, as well as from the emergency update released on January 17, 2026 (which introduced fixes for remote desktop connections and hibernation failures).
As a reminder, Windows 11 23H2 reached the end of support on November 11, 2025, but extended support for organizations will continue until November 10, 2026. If you want to maintain your computer support, it’s recommended to upgrade to Windows 11 25H2 as soon as possible.
Out-of-band (OOB) updates explained
Out-of-band updates are emergency patches released outside the regular monthly schedule. Microsoft issues them to address urgent problems (such as newly discovered security flaws or critical bugs) that can’t wait for the next Patch Tuesday.
These updates are cumulative, meaning they include all previous fixes (security and non-security) plus the new targeted resolution.
Mauro Huculak is a Windows How-To Expert and founder of Pureinfotech in 2010. With over 22 years as a technology writer and IT Specialist, Mauro specializes in Windows, software, and cross-platform systems such as Linux, Android, and macOS.
Certifications: Microsoft Certified Solutions Associate (MCSA), Cisco Certified Network Professional (CCNP), VMware Certified Professional (VCP), and CompTIA A+ and Network+.
Mauro is a recognized Microsoft MVP and has also been a long-time contributor to Windows Central.
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