Be careful – upgrading to Windows 11 24H2 may damage your NAS or storage device

Microsoft General Program Manager Ned Pyle has issued a warning to people running Windows 11 24H2 Release Preview, stating that the operating system may corrupt NAS devices by failing to identify their credentials.

The newly introduced enhanced security measures may impact some third-party NAS devices and USB drives connected to some routers.

As part of the update, Windows 11 will now require SMB signing on all connections by default, which is a problem for incompatible or misconfigured devices.

Windows 11 24H2 NAS security measures

In the post, Pyle explained that the guest fallback feature, which allows users to connect to an SMB server without a username and password, poses a serious security risk: “this means your device could be tricked into connecting to a malicious server without asking in order to obtaining credentials and then receiving ransomware or data theft. It has been disabled in Windows 11 Pro.

Although SMB signing has been available in Windows for decades, its mandatory implementation is new. Pyle added: “Both changes will make billions of devices – not just Windows, but anything running SMB that want to communicate with Windows – more secure.”

However, Microsoft realizes that the changes may cause some users to experience problems when upgrading to Windows 11 24H2 as the system will not be able to distinguish a malicious server from a real NAS device.

Users who experience access issues may see a variety of error messages, ranging from standard security notifications to hidden system errors.

Pyle urges NAS users to ensure SMB signing is enabled, disable guest access, enable username and password protection, and apply firmware updates to bypass the new restrictions.

A new inbox has also been created, [email protected], where customers can share details about NAS devices that do not support SMB signing in order to put pressure on vendors for updates.