After you have connected the Grand device to the PC, on ODIN app you should notice that the: ID:COM will be collared yellow or blue color, and the “added” message will be displayed. If not, that’s means the ODIN didn’t recognize the device, and you will have to disconnect the Galaxy Grand Duos device, close the ODIN app, change the USB port from PC and reinstall the USB drivers once again, after that repeat all the steps from the beginning until everything is working as explained above.