The update is you. Reboot to accept.
Windows Sandbox fails to start. Fix: Run OptionalFeatures.exe and re-enable "Windows Sandbox." Lite versions disable it by default. microsoft.windows.10.pro.1903.lite.version.64 bit
A "Lite" version of 1903 typically reduces the disk footprint from ~20GB to under . RAM usage at idle drops from 2.0GB to approximately 600MB–1.2GB. The update is you