That’s alright 
Milos, do you have a comprehensive backup strategy? If not, please take this shock as a trigger to make sure your data is backed up (remembering that sync is not backup). The more valuable it is, the better your backup strategy should be.
I can’t guess what caused the crash for you today; what is apparent is that actually everything then worked as it should - DT still worked, it protected itself by not automatically reopening the databases, it recognised that the databases were not properly closed, and it will have verified them when you selected “Fortfahren”. You said that you had opened a support ticket - if the logs were attached, then DEVONtech may look into any cause of the crash. Certainly if this experience repeats itself, you should assume DT may be responsible and report using Help > Report Bug (press the Option key to see that menu entry).
Reports of crashes are really pretty rare here in the forum; I trust DT with both my personal and professional digital life. I would not do so if I were worried about the quality of the product.