MKR 1000 not found in port when MKR IMU Shield is connected

Hello,

I am trying to connect my MKR IMU Shield to my MKR1000 by placing the IMU shield in the MKR1000. When I do this, however, the Arduino IDE and Simulink are unable to find the port that my Arduino is connected to.

However, when my IMU shield is not connected to my MKR1000, the port can be found properly, and the code can be uploaded to the board. When I plug my IMU shield into my MKR1000 after the code has uploaded, my project crashes with an error.

Any ideas on how I can correct this so that I can able to connect to my MKR1000 when the IMU shield is plugged in? Thank you for all your help.