Microsoft has blamed Samsung for some devices suffering C:\ drive access problems coincidentally close to March's Patch Tuesday.

Users saw the message "C:\ is not accessible – Access denied" when trying to launch applications, including Office, browsers, and utilities such as Quick Assist.

An access denied error when trying to access the C:\ drive is certainly a bad day for Windows users. The C:\ drive is usually assigned to the first bootable disk partition and is where system files and applications are typically located.

However, for some users running Windows 11 24H2 and 25H2, the C:\ drive became inaccessible, with reports of the issue occurring around the time of the March Patch Tuesday update. There were also reports following the installation of the February 2026 security update.

Microsoft confirmed: "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."

So another example of Microsoft's legendary approach to quality control? It appears not. "The issue has been observed on Samsung Galaxy Book 4 and Samsung Desktop models running Windows 11, versions 24H2 and 25H2," according to Microsoft.

"Microsoft and Samsung investigated these reports and concluded that the symptoms were caused by an issue in the Samsung Galaxy Connect app."

In response, Microsoft temporarily pulled the Samsung Galaxy Connect application from the Microsoft Store "to prevent further installations" and Samsung "republished a stable previous version," which will halt further impact, but is of little help to devices already affected.

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Microsoft said it is "collaborating with Samsung's efforts to develop and validate solutions," but noted that "recovery options for devices already impacted remain limited."

The Windows behemoth directed users to Samsung's support channels for device-specific assistance.

Microsoft has not had a great start to 2026 when it comes to Windows updates. A succession of out-of-band updates accompanied the first Patch Tuesday of 2026. However, in this instance, Microsoft is not to blame for this specific problem.

How a third-party application could wreak such havoc on affected devices, particularly one downloadable from Microsoft's own app store, remains unanswered. ®