New Windows 11 bug breaks Samsung PCs, blocking access to C: drive

Windows 11 updates have been causing all kinds of blood-pressure-raising issues over the last several months. That trend continues with the latest February update, with Samsung PCs now experiencing serious issues after installing update KB5077181.

Confirmed by Microsoft as a known issue in Windows 11, the Samsung Galaxy Connect app is causing “loss of access to the C: drive and app failures” on Samsung PCs running Windows 11 25H2 or 24H2. Without access to the C: drive, PCs are effectively inoperable. Microsoft and Samsung have now published a workaround, however, that will take some time.

Microsoft has reportedly received reports (such as this one and this one) stating that certain Samsung devices lose access to the C: drive after installing Microsoft’s February update as well as some subsequent updates. Affected users see error message “C:\ is not accessible — Access denied.” Access to files is blocked and the launch of certain applications is blocked, including Outlook, Office applications, web browsers, system utilities, and Quick Assist.

By the way: If you’re only using Windows 11 Home, you’re missing out on the many benefits of Windows 11 Pro, which we’ve outlined in our Windows 11 Home vs. Pro guide. The Windows 11 Pro upgrade is available right now in the PCWorld Software Store for just $59 (was $99).

Windows PCs from non-Samsung manufacturers are unaffected.

Which Samsung devices are affected?

Initially, Microsoft’s February patches were suspected. However, a further investigation by Microsoft and Samsung revealed that the Samsung Galaxy Connect app is causing the problem.

Microsoft writes:

While the reports coincided with recent March Patch Tuesday timing, investigation confirmed the issue is not caused by current or previous Windows monthly updates. The issue has been observed on Samsung Galaxy Book 4 and Samsung Desktop models running Windows 11, versions 24H2 and 25H2, including NP750XGJ, NP750XGL, NP754XGJ, NP754XFG, NP754XGK, DM500SGA, DM500TDA, DM500TGA, and DM501SGA.

Regarding how users experience the problem:

Affected devices encounter the issue when users execute common actions, such as accessing files, launching applications, or performing administrative tasks, and do not require any specific user action beyond routine operations. In some cases, users are also unable to elevate privileges, uninstall updates, or collect logs due to permission failures.

There is a fix

Microsoft has temporarily removed the affected Samsung Galaxy Connect app from the Microsoft Store to prevent further installations. Samsung has since re-released a previous stable version of the app, which should mean that no further problems should occur when installing the Samsung Galaxy Connect app (for first-time users).

However, for those who have already installed the broken version of the Samsung Galaxy Connect app and are experiencing the problems described above, trouble continues. There is a fix, however.

Microsoft says that the recovery process will take about fifteen minutes. The workaround to the problem requires removing the Samsung application, then asking Windows to repair the drive permissions and assigning a new owner, then restoring the Windows default permissions, including patching in some custom code that Microsoft wrote.

This story was updated by Mark Hachman on March 17 with the details of the workaround.