Microsoft Confirms Windows 11 Bug Crippling PCs, Blocking Access to Core Drive

"Users might encounter the error, 'C:\ is not accessible - Access denied', which prevents access to files and blocks the launch of some applications including Outlook, Office apps, web browsers, system utilities and Quick Assist."

"Microsoft said the problem has been observed on Samsung Galaxy Book 4 laptops and certain Samsung desktop models running Windows 11 versions 24H2 and 25H2. Affected models include systems such as NP750XGJ, NP750XGL, NP754XGJ, NP754XFG, NP754XGK, DM500SGA, DM500TDA, DM500TGA, and DM501SGA."

"The company emphasized that the issue is not actually caused by Windows updates themselves. Instead, after investigating the reports with Samsung, Microsoft determined that the problem stems from a Samsung application."

Microsoft confirmed a serious bug affecting certain Windows 11 devices that prevents users from accessing the C: drive after installing the February 2026 security update. Affected users encounter the error message "C:\ is not accessible - Access denied." The issue extends beyond File Explorer, blocking common applications including Outlook, Office apps, web browsers, system utilities, and Quick Assist from launching. Users may also be unable to perform administrative tasks or uninstall updates due to permission failures. The problem primarily affects Samsung Galaxy Book 4 laptops and certain Samsung desktop models running Windows 11 versions 24H2 and 25H2. Microsoft determined the issue stems from a Samsung application rather than Windows updates themselves.

Read at TechRepublic