[oahz]

I wanted to make a backup of my phone before I did any jailbreaking.

For some reason my iTunes does not show a backup option.

If I right click my phone while connected it is missing the options (Backup and Restore from Backup). I connected my phone to another computer also running Vista with latest iTunes and it shows this option.

Also, my backup list in "preferences-->devices is empty, so my iTunes is not making an auto-backup during each sync as it should be doing. I completely uninstalled and reinstalled iTunes and nothing has changed.

Any ideas?

[mohda]

I am facing same issue, any idea on how to resolve it ?

[Alpha Zero]

i have a suspicion that this has something to do with the modifications made to itunes awhile back when our iphones would lock up during syncing. i can't remember at all what to search for. if anyone knows what i'm talking about, that might be the answer to fixing that problem.
it was something you had to edit in itunes so that when syncing our jailbroken iphones to itunes, it would not lock up.

[blkcadi]

When you sync iTunes will also make a back up.

[Alpha Zero]

Nope. That is the problem we are having. There is no backup whatsoever. In preferences/devices/backup data it's blank. No backups and no option to back up.

EDIT:
Found it.

Windows Vista:
C: \Usersusername\AppData\Roaming\Apple Computer\iTunes

Windows XP:
C: \Documents and Settings\username\Application Data\Apple ComputeriTunes or
C: \Documents and Settings\username\Local Settings\Application Data\Apple Computer\iTunes

You want to edit the iTunesPrefs.XML file with an XML editor (I used notepad ++). Make sure you make a backup of the file before editing just in case you accidently delete something important.
In the file, search for "backup" it will come to a section that displays:

<key>DeviceBackupsDisabled</key>
<data>
dHJ1ZQ==
</data>

Deleted that and save. Open iTunes and it will ask a couple questions like when you installed iTunes the first time. After that, the backup option is back.
That information was tough to find, so I figured I'd post it here since it's the second result on google if you search "itunes no backup option".

Now time to go swap out my defective 3GS.