For several months I had a problem syncing my Iphone 5 (IOS 7) with my Outlook 2013 on my Windows 8 PC. after trying several things that didn't work, I did an online repair of Office programs, after I made sure that all parties involved are up to date (Itunes, IOS, Office). Immediately after repair sync worked like a charm. Here are the instructions for repair on Windows 8, during repair you will need Office's serial number, or a valid account:
- Press the Windows logo key + X to see a list of commands and options. (Basically a quick way to get to Programs and Features in Control Panel.)
- Click Programs and Features.
- Click the Office program you want to repair, and then click Change.
- Do one of the following:
- In Office 2010, click Repair > Continue.
- In Office 2013, click either Quick Repair or Online Repair.
- You might need to restart your computer after the repair is complete.
For other operating systems see here