Error compiling

Hi, I have som problems,,,

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Build options changed, rebuilding all
avr-g++: error: sketch?? (1) G26_Mesh_Validation_Tool.cpp: Invalid argument

avr-g++: warning: '-x c++' after last input file has no effect

avr-g++: fatal error: no input files

compilation terminated.

exit status 1
Error compiling for board Arduino/Genuino Mega or Mega 2560.
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Were to start looking for errors?

Sorry for my bad english :o

Enable verbose compile output and post the output (enclose it in code tags so the forum doesn't mangle it).