Windows 32 Bit:

1. Close iTunes.
2. Go to Start then Run and type CMD.
3. Run this command(If you right-click on the cmd window you can paste): “C:\Program Files\iTunes\iTunes.exe” /setPrefInt carrier-testing 1

Note: If the command in point 3 doesn't work then please double check the path of iTunes.exe on your computer and use that path instead of the one mentioned withing quotes above.

Windows 64 Bit:

1. Close iTunes.
2. Go to Start then Run and type CMD.
3. Run this command(If you right-click on the cmd window you can paste): “C:\Program Files (x86)\iTunes\iTunes.exe” /setPrefInt carrier-testing 1

Note: If the command in point 3 doesn't work then please double check the path of iTunes.exe on your computer and use that path instead of the one mentioned withing quotes above.