So, I've been on this forum for a few months now and tried many things. Yesterday I took two hours and called Apple support and they finally got it working. I've been syncing and resyncing a few times now, it really works. Here's what I did:
- I visited the support website and clicked through to my problem (iPhone-->Syncing)
- the site asked me to send diagnosis data
- I got an email with a button to send the detailed diagnosis data
- I then called Apple support
- First level support tried it with deleting all data from my iPhone which at first seemed to work but did not
- Second level support (which I got redirected to after the first try) took a look at the diagnosis data and saw that my music app was out of memory.
- He suggested to do a full reset of the phone after at first backing it up on my Mac (not iCloud)
- This downloaded the 7.0.4 software to my Mac (1.4 GB) and overwrote the existing firmware
- Afterwards, I couldn't believe it myself - it worked.
--> Waiting for changes to be applied can take a while the first time. But afterwards it's really fast.
I highly recommend to try this out. The support guys never heard of this problem (Apple support Germany), but were extremely friendly.
I wish you good luck 😉