Some Windows 11 users have recently run into another frustrating issue—a software bug that has left many people unable to access their main C: drive. Microsoft has flagged this issue with its February 2026 Patch Tuesday update (KB5077181) and installing it can trigger the annoying “C:\is not accessible – Access denied” error on your system.
Possible Link to Samsung Share App
Microsoft noted in its official support update that the issue might be associated with the Samsung Share app, although the link has not been definitively confirmed. Regardless, the problem is significantly impacting affected systems by restricting hard drive access and disrupting numerous applications.
What Microsoft Says About the Issue
In its official statement the company said:
“Microsoft has received reports of an issue in which some Samsung device models lose access to the C: drive after installing the February 2026 security update (KB5077181) and subsequent updates. Users might encounter the error, “C:\ is not accessible – Access denied”, which prevents access to files and blocks the launch of some applications including Outlook, Office apps, web browsers, system utilities and Quick Assist.
The issue has been observed on Samsung Galaxy Book 4 and Samsung Desktop models running Windows 11, versions 24H2 and 25H2.
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.”
Microsoft is Investigating the Problem
Microsoft is currently investigating the issue along with Samsung and has said that new updates will be shared once more information surfaces. It has also confirmed that several regions worldwide, including India, Korea, Brazil, and Portugal have been affected.
What Causes the “C:\ Is Not Accessible—Access Denied” Error?
Based on the initial findings, the error seems to be associated with a conflict involving Samsung Share app on some specific Samsung devices. While the root cause is unknown, the bug is affecting system permissions associated with the main drive.
When this happens, Windows may fail to correctly validate access rights for the main drive, which is where the OS and most apps are installed. This may make the system block access to files and prevent programs from launching.
Possible Workarounds Until Microsoft Releases a Fix
There is currently no official permanent fix available as Microsoft is still investigating the issue. But try a few general troubleshooting steps, if you’re lucky, they may help restore functionality.
1. Uninstall the February 2026 Update (KB5077181)
If the issue appeared immediately after installing the update, rolling it back may temporarily restore access.
- Open Settings and click Update & Security.
- Go to Windows Update > Update History.
- Click Uninstall updates.
- Locate KB5077181 and remove it.
2. Check for Samsung App Updates
If the issue is related to the Samsung Share app, updating or reinstalling the app may resolve permission conflicts once Samsung releases a patched version.
3. Use System Restore
If a restore point exists from before the update was installed, you may be able to fix the error by resetting your system to a previous point in time when it was working fine.
- Press Win + S to launch search and open Create a restore point.
- A System Properties dialog box will appear.
- Under the System Protection tab, click System Restore.
- Choose a restore point before the “access denied” error and click Next.
- Confirm the restore point by clicking Finish and you’re good to go. Your PC will restart to apply the changes.
Recover Files If Data Becomes Inaccessible
In case the drive access issue is preventing you from accessing your important files, use a professional data recovery software to retrieve the data stored on the affected drive. Stellar Data Recovery Professional is purpose built for such situations—recover docs, photos, videos, and other files from inaccessible or corrupted drives.
If you cannot access C: drive on Windows has become unreadable or some specific files have stopped opening because of permission issues or system errors… the tool can scan your drive and recover your data to another storage location. This is especially useful when you need to secure important files before trying further troubleshooting or reinstalling Windows.
Bottom Line
The “C:\ is not accessible – Access denied” error seems to occur due to permissions-related conflict affecting certain Samsung devices after the February 2026 Windows update. While both Microsoft and Samsung are investigating the issue, if you’re affected try temporary workarounds—uninstall the update, update the Samsung app, or restore the system.
