Apparently this is a common problem. Backup somehow becomes encrypted when I never set a password, and I've tried every past password on my iPhone I remember without success. I can't decrypt the backup and I can't do an unencrypted backup without that unknown password short of restoring the phone. I can no longer walk around with an iPhone that essentially not backed up! How do I manually backup my iPhone including call details and SMSes so that I can restore the phone and get a fresh unencrypted backup on iTunes?