Hi Chris,
Thanks for the update. Well, that's an improvement at least.
If you close those connections manually, do they close OK, or is the problem only when trying to shut Toad down completely?
Do you have color themes enabled? If so, will you try it with them disabled and let me know if that makes any difference?
FYI, Starting in Toad 16.3 there is an auto-backup system of user files folder. There is a folder right next to it called "User Files Backups". It doesn't include everything in user files by default but it does include workspace and other important files. By default the backup is taken about 1 minute after Toad starts, once per day. So if you start/stop Toad multiple times per day, it only backs up the first time you start it each day.
Oh, also - if a connection has timed out and Toad starts hanging, I have noticed that I can click the red "X" a 2nd time, then "try to restore the program" and it becomes responsive again. Details on this post. Let me know if that helps.
And one more thing - Try turning on freeze detection and posting the log here. That may give us some good info.
-John