I have been warned by my dealer today that he already had two bikes with same symptoms. All fine, all indications on, fuel pump primes after turning the ignition on, hit the start button and there is only one click from the relay. Both bikes were DL1000 2015.
Owner of the first bike called him on the phone saying he was trying to get out of the supermarket Car park and he couldn't start the bike. After a lot of troubleshooting by the phone, the dealer suggested jump start (if that's the right therm for push/starting the bike). Bike started right away. The owner came straight to the dealer. Then he tested everything, starter motor would turn connected straight to the battery but not normally connected.
After a lot of search, he discovered earth connection, down on the engine, completely oxidated. He disconnected it, cleaned it well and tighten it back. Bike started right away.
So, conclusion:
Earth connection (plug) that goes bellow the nut is one type of metal. The engine cover is aluminium. Electricity passing between those two different types of metal will cause oxidation by time. But, if some water hits that spot while electricity is going through, the oxidation will be quick and severe.
So, he removed the nut from the connection again, cleaned it again and applied generous ammount of copper compound lube, then tighten it back. He said that way it should hold for a long time.
He now wants to redo that connection on all new DL1000 bikes that come to his shop for service.
He's great dealer.
Well, he was the one to tell me the story and asked me to write about it here on the forum and warn the members. It's easy DIY job.