I rarely synchronise the iPhone with my Mac, since unlike earlier phones there is so much you can do over the air these days.
Syncing it last night I was slightly confused over why it wasn’t syncing. I unplugged and replugged the iPhone into the Mac. No luck.
A quick search on Google found that sometimes problems arise if you have an USB drive plugged into your Mac. I knew I had plugged in a USB 32GB stick into the Mac, I unplugged it and removed it, and then the iPhone was able to sync no problem.
As a matter of (pointless) principle, since Steve Jobs declared we’re in a post PC world and that everything on the iPad/iPhone would work through the cloud, I no longer ever connect any iOS device to sync. It’s been a number of years now and only a few times has this presented any problems, although sometimes it has needed a lot more effort to do the same tasks.
The worst problem I’ve had in that time though was trying to get tech support from Apple as they kept asking questions about what Mac OS, Windows and iTunes version I was using and gave no option of “none”. They seem to have not taken on board Steve’s vision as the standard help articles they kept replying with kept referring to iTunes etc as if that were the problem rather than acknowledging a bug in the online syncing. Eventually an iOS update fixed it after about 3 months of frustration trying to get them to recognise that the device had never been connected to iTunes.