Contact names not showing for the calls and messages My Galaxy S3 was working great until I installed a firmware update on 26/11/12. Immediately after, the names dropped off the calls and messages and it is now showing phone numbers only. When I dial somebody or receive an incoming call, only the numbers are displayed not the contact name. 

Please help....
Had the same problem with GF's phone. The problem was caused by an update. There are talks of a possible fix on Vodafone.com.au forum via upgrade but the simplest solution, instead of waiting for fix (which may never come to all carriers), is to do a factory reset.

Make sure to make a backup of your phone before doing it because everything will be gone.
Step-by-step for factory reset is available here.