Windows Defender Application Guard and Windows Sandbox have failed to work on the Windows 10 version 1903, 1909, and 2004. The organization is working to fix the issue which prevents the applications from opening. The applications display the error popup “ERROR_VSMB_SAVED_STATE_FILE_NOT_FOUND (0xC0370400)’ or ‘E_PATHNOTFOUND (0x80070003)” when the end-user tries to use the security features. Sandbox is a new functionality of Windows Enterprise and 10 Pro editions. It was made available from version 1903 that allows users to work on virtual systems with Windows 10 basic version. Potentially risky software can be run on this virtual system without affecting the main Windows 10 platform.
WDAG is again a new functionality of Windows Enterprise and 10 Pro editions that are used by administrators to develop a list of trusted local sources and websites etc.
Source: Zdnet