Microsoft has experienced a few months of relatively smooth Windows 11 updates, but the March update has reportedly caused inaccessible C: drives, widespread system BSODs, and freezing. According to multiple reports from Reddit and other online communities, including Microsoft's Q&A forum , the Windows 11 March 2026 KB5079473 update is causing headaches for users. They are encountering issues such as being unable to access their C: drives, system freezing, random reboots, and an overall laggy user experience. While the official March update page shows no known widespread issues, users report that the update is indeed causing trouble in everyday use and increasing the risk of instability. Some Samsung Galaxy Book owners have reported that this update completely blocked access to the C: drive on their devices.

Microsoft has confirmed that the "C:\ is not accessible - Access denied" issue has been acknowledged and that the company is working on a solution. Reportedly, the Samsung Galaxy Connect application is responsible for the inaccessible C: drive, and the issue didn't occur solely because of the Windows 11 March update but coincidentally happened at the same time as other issues that had accumulated earlier. Samsung and Microsoft are collaborating on a fix, making this issue exclusive to Samsung users. The issue affects Samsung Galaxy Book 4 and Samsung Desktop models with Windows 11 24H2 and 25H2, including models with codenames NP750XGJ, NP750XGL, NP754XGJ, NP754XFG, NP754XGK, DM500SGA, DM500TDA, DM500TGA, and DM501SGA.