Cannot compile marlin on Windows 10 - File name too long?

Hi there,

I'm having problems compiling on Windows 10. Something about file name being too long. This Marlin is RC6.

BUT, the exactly same set of files compiles and uploads without any problems when using Ubuntu 14.04.

Both OS has the same, latest version of Arduino IDE.

The error message says:
Arduino: 1.6.9 (Windows 10), Board: "Arduino/Genuino Mega or Mega 2560, ATmega2560 (Mega 2560)"

fork/exec C:\ArduinoIDE\hardware\tools\avr/bin/avr-gcc.exe: The filename or extension is too long.
Error compiling for board Arduino/Genuino Mega or Mega 2560.

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

(Verbose output throws too much data for this forum to handdle, but eventually it fails with the same message)

Using Ubuntu to compile and upload is a PITA because i need to move my printer away from the nice and friendly flat surface, where i have done all the calibrations and printer sits comfortably.
I'd really like to use my laptop with Windows 10 to do this.

Who? What? Where?
Any ideas why Arduino IDE hates Windows 10?