I just followed all the instructions to set up Atmel Studio on a new computer for the ATmega2560. Bare in mind that I have already had Atmel Studio installed on another computer where it worked fine, so I am not a total newbie. I did the following in "External Tools":
I also installed the drivers and generally did the recommended instructions.
However, when I compile a GCC C++ Executable Project, I get the following error every time in any project:
avrdude.exe: ser_open(): can't open device "\\.\": The filename, directory name, or volume label syntax is incorrect..
Keep in mind that I have unplugged all other cables from my laptop, as well as from my Arduino.
And YES the COM ports are matching.