Since I upgraded DEVONThinkPro my database does not open when launching the program. I have tried preferences, last window open but nothing works. Any help? Thanks!
Since I am still in my demo mode, I had noticed the same behavior but thought it was somehow related to not having purchased DT Pro.
Same response will help both of you. 
With your database open, select File > Database Properties. Near the top of the Database Properties panel, check the option to make this your default database. Now DT Pro will always open it when launched.