After updating my game for the 1.9.3.0 patch, the error message 'Launching the game failed; Unable to run program' popped up. so I tried to uninstall the game and install it back again, but now the launcher does not allow me to install the game at the location I want - which is a new folder I made in the D: drive, following the message: 'You do not have permission to install this game at the selected location. Please try a different one'. I am unable to play nor install the game at the moment.
Update: About an hour after, the game installed and worked just fine.
run the launcher as an administrator. right click the icon on your desktop and its the 3rd or 4th option