I've been trying to sync my iPhone over Wi-Fi; however, sometimes it shows up in iTunes, and sometimes it doesn't. It seems completely random.
Yes I have checked the box while plugging my phone in via USB. Yes it always shows up when plugged in via USB. So it's not a hardware issue, it's a software issue.
Welcome to the Support Communities! I've included some information for you that explains how to sync your iPhone with Wi-Fi, and what to do if the it is not recognized in iTunes.
Connect your iOS device to your computer with the included USB cable.
Locate your iOS device. If you're in the iTunes Store, click the Library button, then look for your device in the upper-right corner.
In the Summary tab, select "Sync with this [device] over Wi-Fi."
When the computer and the iOS device are on the same network, the iOS device will appear in iTunes. Then you can sync it. The iOS device will sync automatically when the following conditions are true:
The iOS device is charging.
iTunes is open on the computer.
The iOS device and the computer are on the same Wi-Fi network.
When your device is connected with iTunes via Wi-Fi, you can select the device and then configure sync and other options.
To sync your content to your iOS device through Wi-Fi, you must turn on the option in iTunes:
Connect your iOS device to your computer using the Apple USB cable.
Open iTunes and select your device on the left side of the iTunes window. In iTunes 11, your device will be in the upper-right. You can also find your device by expanding the sidebar from the View menu.
Click the Summary tab.
Scroll to the Options section and select "Sync with this [iOS device] over Wi-Fi."
Click Apply.
Quit and reopen iTunes and restart your iOS device
Restart your home network router using the manufacturer's instructions. You may need to disconnect the power cord for 30 seconds or more.
Note: During this time, Internet services, such as a VoIP-based phone, won't work, and you may need to reset additional network devices.
Check your network connection
Make sure that your Wi-Fi network has an active Internet connection.
Make sure that you connect your iOS devices and computer to the same network over Wi-Fi.
Check for network configuration changes that may interfere with syncing:
VPN configurations
Extending the Wi-Fi network through multiple wireless access points or routers
Guest networks or other security configurations that limit access between devices
Routers that configure different networks for different frequencies such as 2.4 GHz and 5.0 GHz
Connecting the computer over Ethernet
Wake up your computer and open iTunes. If your computer is asleep or iTunes isn't open, the device may not sync.
Update your router. If you're using an AirPort or AirPort Time Capsule, you can learn more about firmware updates. If you're using a router from another manufacturer, contact the manufacturer to ask about available updates.
Check for network interference
If you see performance issues when you sync over Wi-Fi, something may be causing wireless interference:
Microwave ovens
Cordless phones
Physical barriers, such as metal walls or distance between your computer, base station, and iOS device
Try the following to reduce network interference:
Move your iOS device and computer closer to the Wi-Fi router or base station.
Remove your iOS device from any case, stand, or attachment.
Open Safari and try to load a webpage.
Check firewall settings
If you enabled a firewall on your router or computer, make sure that your computer and iOS device can communicate.
Follow these steps to use the built-in firewall option with iTunes on your Mac.
For third-party firewalls and security software, see the developer or manufacturer for assistance.
Mac computers use port 123 to set the date and time automatically. Incorrect date and time on a computer or iOS device can cause connection issues. If you don't know if your router has a firewall or if the required ports are open, follow these steps:
Enable Wi-Fi syncing for additional iOS devices on your network to see if they have the same issue. (See the previous steps to enable Wi-Fi syncing for additional devices.)
If you use another security or firewall software on your computer or router, you can troubleshoot security software issues, contact the manufacturer, or check the documentation to learn how to open TCP ports 123 and 3689 as well as UDP ports 123 and 5353.
All of those may be solutions if the syncing never worked. Except it sometimes works, and sometimes doesn't. So it's not a firewall issue, a router issue, or anything like that; it's a flaw in iTunes since it can't recognize my phone half the time.
I have same problem as buh6173. sometimes my iphone shows up in itunes and sometimes it doesn't - even after using USB cable. In fact it showed up all weekend and then just stopped last night. Its very frustrating to have to troubleshoot every time and nothing works.
Let's be honest here. Step five of the set up instructions is a lie. Wi Fi sync has never worked reliably since it's introduction regardless of the iTunes or iOS version.