Sloeber not working for Duo


Wondering if anyone has the Duo working from Sloeber V4.x?

I have tried to get things going several ways, but when I try to build the Blink example, I get something like

tions/" -MMD -MP -MF"Blink.d" -MT"Blink.o" -D__IN_ECLIPSE__=1 -x c++ "../Blink.ino"   "Blink.o"
arm-none-eabi-gcc: error: Blink.o: No such file or directory
make: *** [Blink.o] Error 1

(this was generated using the makefile in the workspace/Blink/Release directory)

I know that the Redbear Duo json is okay as everything works fine in the Arduino IDE. And, yes, the path to arm-non-eabi-gcc is fine and works.