Upon unmounting the drive with the Epic Games Launcher, one is unable to re-install the launcher because the installer automatically looks for the old drive to install it in. No options to change the path, the installer just gives you an invalid drive error.
https://www.epicgames.com/help/en-US/epic-games-store-c73/launcher-support-c82/what-do-i-do-if-i-receive-the-error-invalid-drive-when-installing-the-epic-games-launcher-a6564
The official solutions to this problem are change your hard drive letter, which is insane because it will mess up all your other paths or is impossible since the main drive must be C. Or use the Windows automated repair tool which takes forever and I’m not sure if that even works.
Trying to manually clear out your registry with all mention of epic games is also far too time consuming, there are hundreds of entries and no one knows which one is the one the installer uses.