Microsoft Confirms Windows 11 Bug Blocking C Drive on Samsung Laptops

Microsoft has confirmed a software bug in Windows 11 that is preventing some users from accessing their main system drive following the installation of a recent security update. The issue, which surfaced after the February 2026 Patch Tuesday release, primarily affects Samsung laptops and has been reported in multiple countries.

The problem occurs on certain Samsung devices running Windows 11 versions 24H2 or 25H2, such as the Galaxy Book 4 series and other consumer models. Users encounter the error message "C is not accessible Access denied" when attempting routine operations, including opening files, starting applications or performing administrative tasks. This denial of access to the C drive, where the operating system and most programs are stored, disrupts normal computer use without requiring any unusual actions from the user.

According to Microsoft's release health documentation, the bug blocks the launch of several common applications, including Outlook, Microsoft Office programs, web browsers, system utilities and Quick Assist. In severe cases, it also hinders users from elevating administrative privileges, removing the update or generating diagnostic logs due to...