Microsoft is off to a difficult start in 2026. For the second time in just two weeks, the company has had to release an emergency “out-of-band” update to fix serious bugs in Windows 11. This latest patch targets a specific problem that caused the Outlook email app to crash and made it nearly impossible for many users to work with cloud-stored files.
The trouble began shortly after Microsoft released its standard monthly security update for January. Almost immediately, users began reporting that their software was acting up. The most widespread issue hits people who store their Outlook data files—often called PST files—in cloud services like OneDrive. For these users, Outlook would either crash instantly or refuse to open at all. Other programs were also caught in the crossfire, frequently freezing or displaying error messages whenever someone tried to open or save an online document.
Microsoft generally only releases these surprise updates when a problem is so severe that it cannot wait for the next scheduled update cycle. Having two of these emergencies in a single month is quite rare and shows just how much went wrong with the initial January rollout. Just last week, the company had to address a different set of headaches: Windows 11 PCs refused to shut down or hibernate, while other users couldn’t log in to their computers via remote connections.
The silver lining for users is that this latest fix is “cumulative.” This means it includes the solutions for last week’s shutdown and login problems as well. You don’t need to hunt down multiple individual patches; downloading and installing this single update should clear up the various bugs caused by the January security update.
If your email has been acting up or your files are giving you trouble, you should head to your Windows Update settings right away. Installing this patch is currently the only way to get your system back on track and stop the constant crashes.
