Many of our customers have come across this issue, and many have unfortunately wiped all their data from their Iphones, or Ipod touches by choosing the 'Erase and Sync' option highlighted below as this appears to be the last resort to get your device to sync.

By noting down a Hex value string on the original Itunes machine the Iphone,Ipod was synced with and inserting that value into the new Iyunes machine (The one that has the erase and sync on it) you can sync with multiple machines.

You will need a Hex Editor, UltraEdit is available as a free Trial from http://www.ultraedit.com/

On the Primary Computer (with which the iPhone, iPod Touch, or iPod was first synced):

- Make sure iTunes is CLOSED!

- Backup the iTunes Library on the machine with which you wish to sync. Backup “iTunes Music Library.xml” and “iTunes Music Library” (or iTunes Music Library.itl on Windows). It is important that you back these files up to a safe location because we will be modifying the files.

- Retrieve your iTunes Library ID. Open “iTunes Music Library.xml” with a text editor (TextEdit on Macs, Notepad on Windows). Find the entry after <string></string> tags, after “Library Persistent ID”. In the screenshot 8B6C633F7DACB74B is my iTunes Library ID. Copy this entry exactly to a piece of paper or email this to yourself. After you have stored the iTunes Library ID you may close the file.

 On the Secondary Computer:

- Make sure iTunes is CLOSED!

- Retrieve your iTunes Library ID. Open “iTunes Music Library.xml” with a text editor (TextEdit on Macs, Notepad on Windows). Find the entry after <string></string> tags, after “Library Persistent ID”. In the screenshot 0E958526D15C67FAis my iTunes Library ID. Copy this entry exactly to a piece of paper or email this to yourself. Do NOT close the file yet!

- Replace the the iTunes Library ID, in my case 0E958526D15C67FA with the one from the computer (8B6C633F7DACB74B-iTunes Library ID from the Windows machine) the iPhone is already syncing with. Save the file, then close it.

 - In Hex Editor open “iTunes Music Library” (iTunes Music Library.itl on PC)

- Choose “Find and Replace” from the Edit menu. Make sure the “Hex” matching is selected not ASCII. Find the iTunes Library IDs you found from both the primary and secondary computers.

- In the “Find” section, enter the iTunes Library ID of the secondary computer and, in the “Replace” section, enter the iTunes Library ID from the primary computer. There should be one match. Save the file and close.

 Success!

You should now be able to sync your devices with two or more computers. Now, you will not be alerted by the annoying “Erase Your Data” prompt from iTunes.