Some users have been reporting that when they try to open Windows Defender Application Guard or Windows Sandbox on Windows 10, it fails to open with error code 0x80070003 or 0xC0370400.

The exact error message is:

ERROR_VSMB_SAVED_STATE_FILE_NOT_FOUND (0xC0370400)
E_PATHNOTFOUND (0x80070003).

Application Guard or Windows Sandbox error 0x80070003 or 0xC0370400

If you face this issue where Windows Defender Application Guard or Windows Sandbox on Windows 10, here are a few things you could try:

Restart your device
Install all the pending Windows Updates
Run SFC and DISM.

Let us see them in a bit more detail.

1] Restart your device

Restart your device and see if the problem goes away. This simple step has been known to help many.

2] Install all the pending Windows Updates

Check for updates for your computer. Maybe Microsoft has released a fix or an update for your system.

3] Run SFC and DISM

Run System File Checker and DISM and see if they help.

To run SFC, in an elevated CMD execute the following command:

sfc /scannow

In an elevated CMD execute the following command:

Dism /Online /Cleanup-Image /RestoreHealth

This will fix any system image corruption from a Windows Update source.

Incidentally, our freeware FixWin 10 for Windows 10 lets you run both SFC and DISM with the click of a button!

Let us know if anything here helped you.

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