Quote Originally Posted by Darrel Taylor View Post

In your .dsn, try setting the Program File in the properties for the PIC chip to the .cof file.
The .cof file is in ... your MPLAB-X project \dist\default\debug
Then save the .dsn
That didn't work for me. In fact, I got it to work by blanking out the file property of the processor in the .dsn file. It seems that MPLABX instructs Proteus which file to use when simulating. But I haven't yet found out why some projects work while others don't...