Alright, thanks @fabiof17 for your quick reply. I’ll take a closer look at the zoom-factor of the viewer and will continue to search for ways to avoid this error. Although I believe here it also happens when there is no viewer node on the nodegraph.
After last days of working in Natron I’m really impressed. This is a great program with a lot of possibilities and as a regular After Effects user I think it’s really competing and at some points even better and more fun to work with. But this issue rises so many times now on different types of nodes here that a lot of node-types throw this error and so can’t be used in a project. This makes the software feel unstable and that’s a pitty for such a great program.
I will continue searching for ways to avoid the error, but at the monent I can’t find anything I do wrong and my system got more then the requirements, so it seems to be something inside the software I’m missing here or there is perhaps an issue in the software.
So I hope anybody on this forum could help me with some clue on when this problem occurs and knows a solution for it.