Thanks Ken,
I gave the chat a try but it was fruitless. Guess I'll try the phone next. For your amusement, here is the chat transcript:
Please wait for a Samsung Agent to respond.
You are now chatting with 'Steffi'. There will be a brief survey at the end of our chat to share feedback on my performance today.
Your Issue ID for this chat is LTK56402532462X
Visitor: HI Steffi
Steffi: Hi, thank you for contacting Samsung Technical Support. How may I help you today?
Visitor: HI, I have an S3 as you saw.
Steffi: Please go ahead with the question.
Visitor: I'm running Jelly Bean too BTW.
Visitor: If you go to Settings|Developer options, there is a 'Desktop backup password' option there.
Visitor: This password seems to be set already on my phone although I have no recollection of ever setting it.
Visitor: I'm wondering if there is a way to reset, or recover that password.
Visitor: Do you know?
Steffi: I am sorry to know that.
Visitor: I'm sorry that you're sorry. ;-)
Steffi: I understand that you want to know whether it has any desktop backup password on the device.
Visitor: I believe there must be. If I try to specify a blank password and create a new password, it just says 'failed to set backup password'
Visitor: You have three boxes there: enter current pass, enter new pass, and enter new pass again.
Visitor: I try entering new pass and new pass again while leaving current pass blank and it fails.
Visitor: I've tried every password I might have ever used in current pass and specify two new passes, but it still fails.
Visitor: Hence, I can only believe there is currently a password set that I don't know.
Visitor: Is there a way to reset that password back to blank, or to find out what it is?
Steffi: Thank you for information.
Steffi: May I know the model number of your device?
Visitor: It's an AT&T Galaxy S3
Visitor: Or do you need to know that number under the battery?
Steffi: Are you referring to SGH-I747?
Visitor: yes
Steffi: Thank you for the information.
Steffi: Please enter the alpha numeric password and check for the result.
Visitor: Enter what password where?
Steffi: Please enter the alpha numeric password in new pass code.
Visitor: You're saying leave the current password blank and enter a new alphanumeric password for new? Please try to work with me; I can't read your mind...
Steffi: I apologies for the inconvenience caused to you.
Steffi: Yes you are correct.
Visitor: OK, before I had tried only characters for the pass. This time I tried 123pass instead for the new and new again. Unfortunately, I still get the same failure.
Steffi: I would like to inform you that alpha numeric pass word means: It should be combined with numbers and alphabets.
Visitor: Yes, that's why I tried 123pass as the password. As you can see, it is composed of numbers and alphabetic characters...
Steffi: I apologies for the inconvenience caused to you.
Steffi: I am sorry I have provided you the information which I have. As we have tried with all the possible pass codes and unable to fix the issue in this regard you need to contact our Samsung voice support team for further assistance.
Steffi: However I will help you with the contact details.
Steffi: You can contact our voice support at 1-888-987-4357, Mon-Fri: 7 AM - 9 PM (CST), Sat: 9 AM - 6 PM (CST).
Visitor: Thanks, I guess...
Steffi: You're welcome. Is there anything else I can assist you with?