Sync iPhone 4 to more than one computer Step 1: Download Hex editor. Step 2: On "Computer B", backup "iTunes Music Library.xml" and "iTunes Music Library " safely. Step 3: On "Computer A", open "iTunes Music Library.xml" with Notepad and search (Ctrl+F) for "<key>Library Persistent ID</key>". Step 4: Following "<key>Library Persistent ID</key>", copy the code between <string> and </string>. Step 5: Find the same code on Computer B, then replace it with the code from Computer A. Step 6: Open "iTunes Music Library" by using the Hex Editor on Computer B. Step 7: Go to Edit > Replace in the Hex Editor. Step 8 Insert code from computer B in "Find", insert code from Computer A in "Replace With" Step 9: Save this file, then close it. Step 10: Open iTunes on Computer B, and plug in your iPhone. Step 11: Select "Manually manage music and videos". S...