I personally use kdevelop since many years now. And despite of the fact that it is not the most stable, and can have some bugs, it remained my favorite free to use IDE. It automatically backup files every X seconds (that you can choose), and can restore them in case of crash. Since kdevelop 5 crashes become exceptional. In kdevelop 4 it could happen seldom.

Another nice thing with the version 5 is that the kdevelop team provides app images to download. So you don't need all the Qt/KDE awful layer to make it work. And this works on Linux, Windows and Mac the same way.

I've been using CLion and it's absolutely amazing. Even better than Visual Studio IMO. The code completion, refactoring, macros, etc. are all top notch and a huge time saver. However, data corruption and lost work can happen with any IDE, and the real solution is version control or a local backup solution (or both).