Microsoft’s first update for Windows 11 in 2026 has been a buggy mess, to say the least. After reports of shutdown issues on some machines, Microsoft issued an emergency update to fix its January 2026 Windows 11 update last weekend. Now, exactly a week later the software maker has been forced to issue a second unusual out-of-band fix to address OneDrive and Dropbox crashes.

Microsoft is also investigating reports of boot failures that could be related to its January 2026 security update.

While the first shutdown bug was limited to machines running Enterprise and IoT editions of Windows 11 version 23H2, the latest out-of-band update fixes crashes and unresponsiveness in OneDrive and Dropbox on the latest 24H2 and 25H2 versions of Windows 11.

Just like the first emergency patch to fix this problematic January 2026 update, the second out-of-band update was released over a weekend, leaving IT admins with a busy Monday morning. There could be further headaches ahead for IT admins, too.

Microsoft warned over the weekend that its January 2026 update may also be creating boot failures on some machines. In an alert to IT admins, the company said it was investigating reports of boot failures with 24H2 and 25H2 after installing the January 2026 update. Some PCs have been bluescreening with a UNMOUNTABLE_BOOT_VOLUME stop code, and Microsoft warns these machines need to be manually recovered.

Microsoft hasn’t completed its investigation into the boot failures, so it’s not clear if it’s definitely this update causing the problems. A similar security update last year was initially blamed for SSD issues, but the root cause was actually early versions of firmware and motherboard BIOS.