Q: Reset iTunes backup password

General information about IOS backups, including encryption: iTunes: About iOS backups - http://support.apple.com/kb/HT4946

help with Iphone backup encryption password lost but stuck on itunes settings - https://discussions.apple.com/message/21834101#21834101 - delete your existing backups: iTunes>Preferences>Devices

https://discussions.apple.com/thread/7044041 - Option to remove encryption not available

About encrypted backups in iTunes - Apple Support - http://support.apple.com/en-us/HT203790

No, that will not do it. The iTunes program and the iTunes backup are separate. You will need to delete the backup and start over again with backups on the device. Make sure you do not select encryption for the new backup. There is no way to restore, recover or change the backup password. Only delete and start over.

From the support document that Limnos provided you earlier, About encrypted backups in iTunes - Apple Support

How can I turn off iTunes backup encryption?

To turn off iTunes backup encryption, enter the password and uncheck the Encrypted backup box in iTunes. Your encryption password is always required to turn off backup encryption.

You can't use an encrypted backup if you don't have the password. If you forgot your password, the only way to turn off backup encryption on your device is to erase your device and set up as new. Erasing removes all data from your device. If you don't want to erase your device, restore from an iCloud backup instead.

I used a really, really OLD itunes password that did unlock my backup....

I did not set up my backup to use a password, I am not sure how it got one that I have not used in years, strange.

My son came up with the idea, and remembered the password. He is a senior at the U of I (UIUC) in EE / English.

Thanks son, your the best and the brightest!

If you forgot iTunes backup password, you can't access to your iTunes backup unless you enter the correct the password. But there is a software called iSeePassword iTunes backup password recovery program could recover your lost password.

This is the guide:

http://www.iseepassword.com/forgot-itunes-backup-password.html

Maybe it works.