Q: Mavericks and iTunes 11.1.2 Won't wifi sync iPhone

1c:ab:a7:a9:91:ba@fe80::1eab:a7ff:fea9:91ba._apple-mobdev2._tcp.local. has already appeared on interface 4. Suppressing duplicate attach notification.

That's it! in my error report too the MAC adresses of my mobile devices are appearing (1. part in front of the "@") But what is "interface 4"?

It is like Bonjour service, discover via IPv6 but failed.

Many Apple services use Bonjour like AirDrop, AirPlay, Wi-Fi Sync seems to rely on it too.

I did some tests, wired all devices to Mac, in iTunes, unchecked Wi-Fi Sync, Applied change, Did a Sync, then checked again Wi-Fi Sync, Applied change. It is basically to re-enable Wi-Fi Sync again.

I did this on 4 devices, all 4 of them are able to be shown in iTunes after that.

I then left Mac and devices there for some time, I didn't close Mac lid, after one night, iTunes was still able to find all devices.

I then closed MBP lid, let it sleep for an hour, waked it up. Now one device disappeared...

I think thomasu's post (Re: Mavericks and iTunes 11.1.2 Won't wifi sync iPhone)makes some senses though I don't know how to solve it.

Thanks, that worked for me.

Only restarted my modem and my access point and my iDevices appeared again in iTunes.

This worked for me when my iPod Touch wasn't showing up in iTunes after the iOS 8 update. It's only been a short time since I did it, so it may not last, but I'm keeping my fingers crossed.

1. Uncheck "Sync with this iPod over Wi-Fi"

2. Click "Apply"

3. Close iTunes

4. Reopen iTunes

5. Check "Sync with this iPod over Wi-Fi"

6. Click "Apply"

7. Unplug iPod (iPod icon remains in iTunes sidebar)

8. Click "Sync"

Put your Mac to sleep mode (close the lid for example), wake it up after one hour, some of devices disappeared again from iTunes.

Yes !!

10/5/14 5:05:17.062 PM com.apple.usbmuxd[26]: HandleDeviceAttachHelperCallback preflighting failed for WiFi device 0x30-fe80::7e6d:62ff:fecc:1b8b:0: 0xe8000084. Ignoring device.

restarting my Idevices while my Mac is powered on but iTunes not opened..

1. Power on your mac
2. get connected to a wifi
3. restart all your idevices (iPad,iPhone)
4. connect idevices to the same wifi that your mac is connected to
5. open up iTunes in your mac and TADA …. it worked for me …

Have done that a couple times.  Only a temporary solution, problem arrises after a couple of syncs.  So this is still an issue a year after the original post? Frustrating.  Can this be fixed yet?!?

I see the coincidence that the departure of good products from Apple coincided with the departure of our beloved Steve Jobs.

1. When the iPhone 6 is announced three or four toxic "update" to the iPhone came along that turned Siri into a complete idiot. Were we supposed to rush out and buy a 6 to escape from the crummy updates to our iPhones?
2. When the newer operating systems came out for our iMacs and MacBook Pros, Apple announced the for pay "Cloud" at the same time as Apple shut down local backups of our iPhones using our Macs. Were we supposed to rush out and buy an expensive Cloud to escape from the crummy intentional removal of iPhone backups?
3. Time Machine went along just fine, but then Apple made it so that you couldn't do a fast backup to an external drive hooked up directly and THEN move the drive to the Apple Airport Extreme. They turned that off at the same time as they beefed up the very expensive Apple Time Capsule device. Were we supposed to rush out an get a Time Capsule device to escape from the intentional removal of backup drive connection freedom?
4. Time Machine used to back up all my Macs. It did this faithfully for YEARS. Now a Time Machine regularly gives the message, "for the sake of your backups I will now completely erase all of them because I was never programmed to repair a slightly-corrupted Time Machine backup file. I don't know or care about your backups. Neither does Disk Utility. Neither can fix a perfectly operational backup data package (entering Time Machine you can see the backed up data works just fine). Were we supposed to rush out and get an expensive non-Apple WiFi backup system? Why not just tell us this instead of intentionally destroying our backup files while innocently-sounding the encouragement to just throw away all our backed up data for the convenience of the now-deeply-flawed Time Machine system.

Steve was the driving force. Without him Apple is just as lost as every other greedy company, now.

Sherman

I found a fix that worked for me. It seems to me that iTunes WiFi sync is just a very intolerant feature - you deviate much from Apple's ideal setup and it doesn't work.

In my case the fix was to disable my second network adapter. I have a second NIC connected to an unroutable network (a "dead end") that is not on the same VLAN as the WiFi. Shut down, removed the second NIC, works fine. So obviously iTunes was looking for my iPhone on that. If I were a AMDS/Bonjour dev I'd be checking on all interfaces intermittently and sticking with one until the device drops out again, rather than trying to use an interface with an APIPA address...

I only use my iPhone in my car now, so it lives in there. With WiFi Sync working, I can now drag and drop new music onto my iPhone while it's still sitting in my car. Very happy!