So I'm pleased to report this evening that I have resolved the issue. I was lucky enough to have my neighbor's iPhone 4S units, and mine as well, all experiencing the issue, so I have several reproduceable test cases.
The symptoms were as described in the original poster's note. It looks like the song is playing, but nothing plays. You'll also find that trying to play the same music through the headphones, often, but not always causes the issue. And in my cases, Siri is unable to start playback of music. Note that this issue can effect users that connect their iPhone to their car via a USB cable as well.
The symptoms that trigger this tend to cluster around a few common issues:
- You are an upgrader and setup your new device from a backup in iCloud
- You are upgrading an existing device where you did a restore, and then the restore was from iCloud
- When you visit "Purchased" on the device, and then select "Not on this iPhone" you see a list of missing tracks; yet when you do a sync (whether over Wifi or cable) to your computer, it reports everything synced correctly. If you try to download the tracks on the device itself, some will constantly reappear as needing to be redownloaded, even though they are present
- The device appears to be able to randomly play a track only later to refuse to play the track. The symptom is that the device appears to be playing, but the timeline is frozen
- Often, when the issue occurs, the device reports "XXX items could not be synced" and then reports that you should check iTunes for more information -- except iTunes shows no further information
If any, or all of these items are occuring, there's one place to check to see if you've been bitten by what I like to call the partial restore/sync bug with iCloud:
- While selecting the device in iTunes on your computer, attached via a cable, click on the device. To the left of the device name, should be a small triangle. If you cannot see items beneath the device name (like Music, Apps, Books) click on the triangle. Next, select Music. When you see the list of the tracks on the device, you'll see a column on the left side which may be populated by small "sync-like" symbols next to the track names. The song will often be ghosted out.
- If you see this condition, which I call the "zombie state" -- you are effected by the problem. The issue is that iTunes thinks the device will download the songs and doesn't write them on a sync; it's as if "placeholder" files are there, but not all the data. Interestingly, removing all music from the device and resyncing it doesn't clear the problem. And there's no way to get the device to "restart" downloading these items from the cloud. So far, every user with this problem did an iCloud restore which got interrupted before all the music and apps could download. The most common cause is an interruption in WiFi.
So far, in my testing the only reliable way to clear this conditon is to do the following, all while tethered to your desktop computer:
- Do a complete backup to the computer
- Do a restore
- Do NOT restore from the iCloud backup, instead, wait for iTunes to sense the device and offer you the "Setup as new" or "Restore from a previous backup"
- Restore from the backup you just created and sync
Re-check the music section of the device upon completion; you should see no items in the zombie state.
In my testing this evening, the device performed as expected, with no issues around device control, Siri, or track selection.
Hope this helps,
Matt
