On Mathematica 10.3 running on Raspberry Pi 3, the debug session on the Front End hung and I had to kill the Front End. ( I now know better: better 'kill -9' the Kernel process and not the Front End).
Anyhow, now the Front End will not start. The front end attempts to start, displays the Wolfram logo, reports "initializing the kernel", then momentarily displays the debug window and then shuts down.
Importantly, the wolfram command line session starts okay.
How can I recover from this situation?
/home/pi/.WolframEngine/SystemFiles/FrontEnd has no large files there or obvious locked items.
I cannot find any logs from which to debug this.