Saved iPhone on new MacBook Pro w/o encryption password, now restore asks for password.

I have a new MacBook Pro.

I plugged in my phone and backed up the phone in iTunes. I never selected encryption and never entered a password.

Apple store gave me a new phone to replace failed phone I brought in to be fixed.

I select 'Restore' from iTunes backup and it is prompting me for a password I never provided in the first place.

What can be done to restore from backup when I never entered an encryption password?