You asked about iPhone, but I expect that this process I now have to use with my iPad may also work for the iPhone. I was having the same problem of iTunes not seeing my iPad the last few days, but then I found a way to get my iPad to sync. Here is what works for me:
1) Shut off computer.
2) Shut off iPad.
3) Turn on both devices.
4) Open iTunes on computer.
5) Select iPad in iTunes on left side of iTunes (one click) on computer.
6) Click on sync in lower right of iTunes.
This works every time for me, but I don't ever remember having to shut off both devices in order to be able to sync before I updated to iOS 6 on my iPad. Now, I have to go through this whole process or else it won't sync. I also noticed that clicking on sync on my iPad does not work since I updated to iOS 6. Apparently iOS 6 has messed up sync, but at least I found a way to get it to work for me.
Other half has had the same problem but now resolved.
Try the following as it has fixed it.
- Plug in with sync cable
- Un-tick 'sync with wifi' box
- Sync iPhone
- Tick 'sync with wifi' box
- Sync phone with cable
- Unplug cable
- restart computer
On restarting mac, it took a couple of minutes and then it found her phone.
Hope this is helpful
This is obviously an iPhone 5 issue...since both Mac and Windows is having the same issue. I've tried all the tricks recommended here (and thanks for the advice) and still no Music sync. I guess I'll just wait till a fix comes through! And the wierdest thing is... after doing the full reset.... all the songs now show in the iPhone 5 but it does not show usage (ie Memory being taken up either on the iTunes bar nor in the iPhone5 itself!)
Okay I fixed it. The problem was actually the name of the iPhone. Since I did a restore I had the same iPhone name as my old iPhone 4S "Christian's iPhone". The second I came in and changed the name to "Christian's iPhone 5" it poped up instantly after I unplugged the cable. iTunes must have been waiting for my old phones identifier to show up on the network. Anyway it's a good fix. Thanks!
OK OK OK
I tried all of the above ideas
none worked for me!
I had already re booted, but I rebooted again, the phone, router, comp (iMac)
I changed the name of my phone, I had a lot of hope riding on that idea, it sounded good, but (sigh) no go!
finally I got it working
this is what I did, I hope it works for you (at least on a Mac)
system preferences - Sharing
I clicked on internet sharing, but did not 'tick' the box (mine was off & is still is off now)
I 'ticked' the Wi-Fi tick box
and got out of preferences (i did not 'tick' the internet sharing box, dunno if that is importiant, just what i did)
my iphone 5 popped up in iTunes over Wi-Fi in like 5 seconds and has stayed there since i did a wifi sync