iPhone 4S ask for backup file password after I updated my phone to iOS 5!
I've updated my iPhone to iOS5 version and everything was working except the part where I needed to provide a password to achieve my backup file. I have not put any passwords for my backups before. Now; I’ve got lost all my messages, calendar appointments and contacts, unless I have the password. Assist me, any suggestion is going to be appreciated much.

I do not want to recover previous backups I only want to create new backups which are unencrypted so I can be sure that I will be able to restore my iPad without being asked for a password I did not enter, but apparently until I input the aforementioned password

As part of the advice I received from the Apple tech I deleted all my historic backups (unencrypted and the last which was encrypted) and tried recreating a new one. This was also encrypted.
Due to the fact I am running iTunes on Windows I cannot access keychain to recover iPhone 4S backup password.

Apparently the password is not my current PIN, my current windows admin password (I thought this would be unlikely but it was the Apples phone tech’s advice so I thought I would try it).

ANY 4 digit number or combination of such (had to run Tenorshare iPhone Backup Password Unlock Tool to determine), any word in the English language with minimal mutation (again courtesy of Tenorshare).
For details on how to use Tenorshare iPhone Backup Password Recovery please read:

1: Download tool “iPhone Backup Password Recovery” from site http://www.windowspasswordsrecovery.com/product/iphone-backup-unlocker.htm , install and run it. Then software will guide you to find the saved encrypted 4S iPhone backup file path.

2: Choose your right Attack Type and do the proper settings
Totally, you’ll find 3 modes to select: Brute-force Attack (try all possible character combinations), Brute-force with Mask Attack (Once you know some symbols in the password) and Dictionary Attack (your personal dictionary or use import default dictionary)

3: Remove encrypt iPhone 4S backup password
After choose your suitable attack mode, after this you cost minimal time to find password and get lost data on your phone!

So basically unless I want to run a comprehensive brute force attack on the backup to determine the password (Tenorshare surprised iPhone Backup Password Recovery calculates resolution within minutes) then my only other option is to lose a lot of data and more of my precious hairline.

Get video on what to do if Fogot iPhone 5 Backup Password!

Source: http://resetpassword..com/2013/01/iphone-5-ask-for-backup-file-password.html