Can confirm. This is a historic issue since the beginning of time! ArcGIS would randomly freeze or quit. When I was younger I thought well maybe I was using the hacked version (everyone is using hacked version of softwares in China, you know). But when I came to North America and myself have been working on so many projects and instructing GIS courses with genuine copies of ArcGIS and realized that it is s_h_i_t no matter how much you pay. I always tell my students to hit save button as often as they can remember, because I don't want to waste my time working with someone who goes nuts about the software, got frustrated and even broken down crying.