Microsoft is rolling out another August cumulative update (KB4512941) for Windows 10 version 1903 that includes numerous fixes, including one for the Windows Sandbox crashes. This update won’t download and install automatically unless the user manually checks for updates in the Settings app. […]

from https://www.bleepingcomputer.com/news/microsoft/windows-10-v1903-update-kb4512941-released-with-sandbox-fix-and-more/