2. First, enter cydia to see if the plug-in appsync is installed. If not, there will be no problem after installing the plug-in appsync. Just try it.

3. Driver problem, uninstalled, reinstalled, try again, or use synchronization assistant, 9 1 assistant.

It can also be quite useful, so I'll use 9 1.

If it doesn't work, there may be something wrong with the 4S system. Turn it off, Baidu will check the iPhone DFU mode, follow the prompts and iTunes will respond (if there is no response, it may be the relationship between the data interface and the computer driver). Click to restore and reinstall it to see if the problem is resolved.

5. the data interface of your iPhone4s is not good. If the same data cable is used, 4s can't touch it, which means it's not the data cable, but the interface.

Personally, I suggest using 9 1 or synchronization assistant. I think Itunes is not easy to use and games are hard to find.