Windows 10 remove System Drive after 1803 upgrade Posted on September 6, 2018 - September 6, 2018 by vrpc This is what worked for me: start; CMD right click select Run As Administrator mountvol <Letter of the Drive> /d resource: https://support.microsoft.com/en-us/help/4337524/windows-10-april-update-new-partition-appears-after-installing