To diagnose and fix ChromeDriver crashes, you have a few options. This is only for ChromeDriver crashes, which is not the same as Chrome crashing or closing.
On Windows, you'll see something like this:
Create a repro case
Create a repro case that ChromeDriver contributors can use to reproduce and debug the problem. It's ok if the crash does not occur 100% of the time. File a bug with your repro case. This is usually the fastest option to get help.
Get a dump of the crash (Windows only)
To create and debug a crash dump, you need a debug version of ChromeDriver. We don't currently have official releases of debug build of ChromeDriver, but you can check out Chrome sources and build the debug version of ChromeDriver. See the contributing section for help. When the crash happens, attach the debugger and see what is happening. This requires some C++ experience and knowledge of your system's debugger.
Configure your system to create a fulldump on crash. See Microsoft's Collecting User-Mode Dumps for help.
After a crash dump is created, use WinDbg to analyze it:
<ctrl-d>` and choose dump file
!sym noisy # just to show any problems we have finding symbols
ld chromedriver # or !reload
lmvm chromedriver # Should show chromedriver has private/debug symbols
!analyze -v # Tells windbg to analyze the exception