6.2.3.3 Import Atmel Project - Select Compiler
Step 3 or 4. Select Compiler
This window will highlight the compiler from the imported project, if MPLAB X IDE can locate it. If not, you may select a compiler from the list. However, if it is not the original project compiler, you will notified.
It is suggested that you keep the original project compiler until after import to ensure your project is working correctly. Then you can select a different compiler in the Project Properties dialog.
If you do not see a compatible compiler listed, click Cancel and follow the directions under Create a New Project, 5.1.6 Step 5: Select Compiler.