XBMC not shown on screen on mini

Hi,

I had XBMC running (almost) flawlessly on a 2012 MacMini when I tried to solve the problem of theMini's volume being activated by my Harmony and installed Candelair. This solved the volume problem but created new ones, so I uninstalled Candelair again. Now XBMC no longer appears on the screen when I switch to the mini using the Harmony remote. It starts the mini correctly and I believe it also starts XBMC correctly but nothing shows on the screen. When I start Rowmote on my iPhone, the screen suddenly comes on. This suggests it is a focus issue. But what can be done about it?

I seem to be answering my own questions but I think I may have identified the problem. After some searching I discovered that XBMCHelper was not running in the background. After some tinkering it suddenly came back (I wish I knew how I had done that; was it the reinstall of XBMC or the restart of the Mini that followed it?) and all was hunky-dory again. I haven't checked it yet now that it is the morning after, but I hope all will be well. Can anyone tell me how to restart the helper when for some reason it is no longer running?