Facepalm: In what looked like yet another Windows update horror story, Samsung PC owners started reporting that their systems were suddenly refusing access to the C: drive. Affected users saw "Access denied" messages that were breaking everything from Outlook and Office to browsers, system tools, and Quick Assist. But Microsoft is pointing the finger elsewhere.
Because the failures appeared around March Patch Tuesday and followed recent security updates, plenty of people blamed Microsoft's latest patches. Now, the company says the real culprit was not Windows itself, but Samsung software.
Microsoft has added the issue to its release health pages for Windows 11 24H2 and 25H2, where it says some Samsung devices lost access to the system drive after installing the February 2026 security update KB5077181 and later updates.
Image credit: Vishuakade (Samsung forums)
That timing made the bug look update-related, especially as reports continued into March. But after investigating with Samsung, Microsoft says the symptoms were actually caused by a problem in the Samsung Galaxy Connect app, not by current or previous monthly Windows updates.
"Microsoft and Samsung investigated these reports and concluded that the symptoms were caused by an issue in the Samsung Galaxy Connect app. While the reports coincided with recent March Patch Tuesday timing, investigation confirmed the issue is not caused by current or previous Windows monthly updates," Microsoft wrote.
The scope seems fairly specific, though that will be little comfort to those impacted. Microsoft says the problem has been observed on certain Samsung Galaxy Book 4 laptops and some Samsung desktop models running Windows 11 versions 24H2 and 25H2.
The bug can cause users to lose access to files on the boot drive, apps to stop launching, and in some cases even basic administrative tasks become difficult or impossible.
Microsoft says the affected version of Galaxy Connect has now been temporarily removed from the Microsoft Store, while Samsung has republished an older stable version of its Galaxy app to keep more systems from being caught out.
The bad news, according to the Redmond firm, is that recovery options for PCs that are already affected are limited, which suggests anyone already locked out of C:\ may still be in for a frustrating time. Microsoft said it is "collaborating with Samsung's efforts to develop and validate solutions."
The episode is still a bad look for Microsoft, even if Samsung appears to have supplied the broken component. When a bug surfaces immediately after a Windows security update and leaves users unable to access their system drive, most people are not going to stop and wonder whether a preloaded OEM utility was the real problem. They are going to blame Windows first – understandably so. This time, though, Microsoft says the timing only made the update seem like the culprit.