Following the February Windows 11 update (KB5077181), some Samsung devices, particularly the Galaxy Book 4, are experiencing an error that prevents access to the C: drive, displaying the message "C: is not accessible - Access denied." This issue affects users' ability to access files, launch applications, and perform administrative tasks, locking them out of essential programs like Outlook and Office applications. Microsoft has acknowledged the problem, but the root cause remains unclear, possibly linked to the Samsung Share application. Users have suggested risky workarounds, such as modifying C: drive security permissions, but these may lead to further complications. The recommended safer options include uninstalling the update or waiting for an official patch from Microsoft.