Microsoft and Samsung scramble to fix a major C: drive lockout bug on Galaxy devices — faulty Galaxy Connect app leaves users with 'limited' recovery options following recent Windows 11 update

An unusual new bug that prevents Windows 11 users from accessing their main C: drive on Samsung devices has been identified following a recent system update. A preliminary investigation by Microsoft and Samsung has placed the blame on a Samsung-specific app, rather than an issue with the Windows 11 update itself.

The message “C:\ is not accessible – Access denied” became visible when trying to launch apps or access files on affected devices after installing February 2026 security updates (KB5077181) on certain Samsung devices, including some Galaxy Book 4 laptops and Samsung Desktop models, according to Microsoft in a notice posted online.

The notice confirms that the issue prevents users from launching certain apps, “including Outlook, Office apps, web browsers, system utilities, and Quick Assist.” The report also notes that affected users are unable to access files on the C: drive or perform some administrative tasks. It also prevents users, in some cases, from removing updates, accessing certain system logs, or elevating their user access privileges.

Microsoft confirms that an investigation of the reports, alongside Samsung, identified an issue with the Samsung Galaxy Connect app. The app itself has been removed temporarily from the Microsoft Store, while Samsung has rolled back to a previous version of the app to stop it from appearing on other devices.

Unfortunately, Microsoft also confirms that “recovery for devices already impacted remains limited,” but the company is working with Samsung to “develop and validate solutions” for those who face problems.

No further information is available at the moment, although reports on Reddit suggest the problem relates to broken Access Control Lists in Samsung’s factory image for Windows that trigger when the Samsung Galaxy Connect and Galaxy Share Folder apps are updated. The same Reddit post in the r/sysadmin subreddit also suggests some potential workarounds, although these haven’t been tested or verified by Microsoft, and require some extensive changes to your drive permissions that change the ownership of your entire drive, which isn’t recommended in the long term.

If you’re running one of these devices, including models NP750XGJ, NP750XGL, NP754XGJ, NP754XFG, NP754XGK, DM500SGA, DM500TDA, DM500TGA, and DM501SGA, you may want to remove the affected app from your device or roll back to the currently recommended version as soon as possible. Should your device be affected by a loss of access to your files, however, you’ll have to hold tight for an official solution.

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