I took a look into the Windows event viewer. The PiTool crashes are logged there.
Application name: PiTool.exe
Module name: ucrtbase.dll
Exception Code: 0xc0000409
Process ID: 0x354c
Starting time: 0x01d46bb85ae7ef65
Application path: C:\Program Files\Pimax\Runtime\PiTool.exe
Module path: C:\WINDOWS\System32\ucrtbase.dll
The exception code is interesting. According to https://msdn.microsoft.com/en-us/library/cc704588(d=lightweight,l=en-us,v=PROT.10).aspx this exception code indicates a stack overflow.