Anyone on 2018 done this yet? I backed up all my old projects today and threw them on a portable drive to clear up some disc space on my tablet. After making sure they were safe, I proceeded to uninstall 2016. Tried to open 2018 and said there was no program associated with the shortcut. No softplan exe file in the 2018 folder. I was able to pull over some stuff from my desktop to get softplan to open but then found I had no symbols, no openings, stairs, etc. Downloaded the additional content and still had nothing. It appears that the 2016 folder that is created when you upgraded to 2018 has a lot of necessary files intermingled in it and deleting that folder will completely screw things up. I've lost a full day of work when I'm already about 2 weeks behind and now it appears that the only solution is to uninstall everything completely and start fresh with a new install of softplan.
Be awefully careful if you have both on your computer and decide to uninstall 2016 like I did. Not a happy camper today.