I use the free Davinci Resolve regularly (not sure which OS you're on) and it is stable on both Mac and Windows. Haven't tried on Linux since install on non-Ce

I use the free Davinci Resolve regularly (not sure which OS you're on) and it is stable on both Mac and Windows. Haven't tried on Linux since install on non-Centos is a little complex. If not using Davinci Resolve, I recommend Shotcut, which is a very capable, easy-to-use, cross-platform, open-source, and probably the most stable free open source editor out of others (ie Kdenlive, Openshot, etc).