A recent Windows 11 update from Microsoft has caused significant issues for owners of Samsung Galaxy Book laptops. Users have reported losing access to the crucial C drive, encountering an error message stating “C: is not accessible – Access denied.” This access block has prevented users from opening files and running certain applications like Microsoft Outlook, Office apps, and select web browsers.
The affected laptop models include NP750XGJ, NP750XGL, NP754XGJ, NP754XFG, NP754XGK, DM500SGA, DM500TDA, DM500TGA, and DM501SGA. Microsoft has acknowledged the problem, attributing it to the February 2026 security update (KB5077181) and subsequent updates.
The issue seems to stem from Samsung’s Galaxy Connect app, which facilitates screen mirroring, file sharing, and data transfer between Galaxy smartphones and Windows PCs. The app has been temporarily removed from the Microsoft Store as a precaution, with a stable previous version reissued to prevent further installations.
While the timeline for a solution remains uncertain, Samsung and Microsoft are working together to address the problem. Owners of Samsung PCs are advised to hold off on updating to Windows 11 versions 24H2 and 25H2 until a fix is in place. Users currently on these versions should refrain from updating further until the issue is resolved.