I rebuilt database and things worked better but still crashed after perhaps placing 10 or so segments. I'm trying to place "TRS19" track from the standard built in available track, several different ones including some TANE and other track (but all built in). In addition to my iMac I also have MacBook Pro and I get the same results it it. (Believe it or not, TSR19 Driver runs as well on the MBP as it does on the iMac.) (Both at lowest quality settings)
The DBR cleaned up some of the data corruption caused by previous crashes, and that's good. The fact that you still crash means something else is going on and I don't think it's the program its self. Sadly this could be hardware overheating causing this.
Does this also occur on both your machines or only your iMac?
How long does your machine run before the program crashes?
I'm familiar with Mac hardware only because I used to support some users in the office where I worked, however, I don't normally use a Mac. What I do remember about the machines from that era, ca. 2010-2013, is they got really, really warm.
TRS19 is very CPU, RAM, and GPU intensive. When the programs operate, they generate heat and the harder the system operates, the more heat is generated. If there is inadequate cooling in your system, this can cause things to get 'touchy' and cause the programs to crash, or worse the hardware to completely shutdown.
From a hardware standpoint regardless of being a Mac or "PC", will shutdown if it gets too warm. This is actually a safety feature to prevent the components from burning up. The system will first slow down, then eventually turn off. This works to a certain extent, but there are some components such as RAM (memory DIMMS) that can become overly sensitive to heat or cold and when they are affected by the heat, they cause the system to crash outright. Way back in my hardware technician days, ca. 1980s, we would use freeze spray and a heater to force components to fail if the system was experiencing untraceable crashes.
So unless Tony can confirm it's software, I definitely suspect hardware here.