Apparently we keep on running into this issue once in a while. While developing you run your objects from the Objects Designer and with each single execution a new Windows Client session is being fired. Using your valuable time and frustrating your debug session as the previous one is not valid anymore and you have to start a new one. If I recall this right it first happened when NAV 2013RTM and R2 were installed side-by-side and we got a fix for that from MS.
In the meanwhile I didn't get bugged by this until a couple of weeks ago after I created a new Azure machine for NAV 2016 which contained CU 3. As I was busy preparing various courses and needed my time for that I didn't allow myself to fix the issue, somewhat annoying my students, with every other object I launched from the development environment. Triggered by this old post showing up in my dynamicsuser RSS-feed subscription (another annoying phenomenon), and having some time today, I decided to get this thing solved for my NAV 2016 CU 3 installation.
The old post was too old for my issue, but from this I got to others. Through NAV RTC is opening for each run of object I eventually bumped on this one that helped me out fast and easy. Thanx Chris et al.
To prevent myself from having to search again next time this small blog post.
Good to hear, Maarten. The same happened to me. And apparently to more, getting some more reactions to this post.
For example Jason Down, who first noted that it did not work for him, to find out later that it did help, but only trying again "stopped service first and made sure both rtc and dev env were shut down. It worked this time! Thanks Luc :)"
Saved my own day a couple of times again. 😉