Microsoft says it is working on a fix for a bug that prevents Windows Sandbox and Windows Defender Application Guard from opening.
The problem affects versions of Windows 10 1903, 1909 and 2004. When it does not open, the error triggers the error message ‘ERROR_VSMB_SAVED_STATE_FILE_NOT_FOUND (0xC0370400)’ or ‘E_PATHNOTFOUND (0x80070003)’.
Windows Sandbox is a relatively new feature of the Windows 10 Pro and Enterprise editions since version 1903 that allows users to launch a virtual machine with a basic version of Windows 10 to run potentially suspicious software without the risk of affecting the main installation. Windows 10.
The feature has proven popular with IT professionals due to its ability to safely run potentially risky executables in a container, and Microsoft included several enhancements to Windows Sandbox in Windows 10 version 2004.
Windows Defender Application Guard (WDAG) is also relatively new to Windows 10 Pro and Enterprise editions that administrators can use to create a list of trusted websites and local resources.
WDAG comes into play when users access a URL outside of that list. Launch Microsoft Edge in a Hyper-V container to keep the browser isolated from the operating system. Microsoft released WDAG extensions for Chrome and Firefox last year.
“To mitigate this problem after receiving one of the above error messages, you will need to restart your device,” explains Microsoft in a support note.
Microsoft plans to address the bug in a future version of Windows 10. However, it has not said when the solution is expected to arrive.
The company hasn’t listed the problem in its Windows launch status panel for any of the affected versions, which may be because there is a simple solution.
As Bleeping Computer points out, a similar problem affected Windows Sandbox in Windows 10 Insider previews last year after users installed update KB4497936.
