Windows 11 KB5078127 emergency update (25H2) fixes Outlook POP, PST crashes, unresponsive apps after January 2026 Patch Tuesday

The Windows 11 KB5078127 emergency update, also known as 25H2, addresses issues with Outlook Classic (POP, PST) crashes and unresponsive apps following the January 2026 Patch Tuesday. This out-of-band patch is mandatory and fixes severe problems affecting various apps on Windows 11. The update can be found on the Windows Update page and takes about 5 minutes to download and 3 minutes to install. It is the second emergency update for Windows 11 in less than ten days, following the optional KB5077744 release.