I have been playing around with elementary for a couple of months. It is pretty good. one of the few that does not give my video playing a hard time by continuously freezing but that is another problem, anyway the current problem is yesterday I decided to pull the ssd drive I had elementary installed on to install another os (linux mint 19) on another drive. I completely forgot about the efi so when I placed the ssd drive back in, I now get an error message about inserting a valid boot disk. In other words, I need to fix the efi to accept the drive again without having to reinstall. I know this is possible most linux distros, just don't know the steps for elementaryOS. any help would be appreciated. -------------------------- just an update. I decided to re-install. so disregard