I had a lot of problems with this and spent two hours with high level Apple support, to no avail. Syncing would hang at preparing to sync, or syncing calendars, and go no further.
We reset sync history, completely uninstalled and reinstalled iTunes, totally restored my device, restarted the mobile sync services, and so on. Nothing fixed the problem. iTunes refused to sync with Outlook.
I also use Eset Smart Security, but I did nothing with that, since it worked fine with earlier versions of iTunes.
After sleeping on this, fretting that the days of syncing my Outlook calendar were behind me and I would have to rely on iCloud (ugh), I finally solved the problem myself by doing all of the steps below (and unfortunately I had to redo them all after Patch Tuesday rebooted my computer last night, but in the end it takes only a few minutes).
I am not sure which of these steps is essential, but none is particularly difficult, so no harm in doing them all :
Close iTunes.
Do a hard reset on the device (not a restore!).
Go to Start> Services and stop and restart Apple Mobile Device (highlight and right click on it, so these options appear).
Go to Control Panel> Programs and Features.
Then find the following three programs, and for each one highlight, right click and choose Repair:
Apple Application Support
Apple Mobile Device Support
iTunes.
Restart iTunes, attach iPhone.
Worked for me....
Calisson
Windows 7 64 bit
iTunes 11.1.5.5
iPhone 5s and iPad Mini both running iOs 7.1
Oulook 2007