Unfortunately, contacts has stopped error comes up. Most of these issues comes from the cache google stores in the local storage to speed up the process of re-downloading from Google servers and to reduce the load or when a second app / settings becomes incompatible. This particular issue is specifically related to Google+.
Errors are usually populated when the servers and the device are out of sync, an example would be if something has updated on the server yet the phone is still looking into its local storage (cache).
Steps to fix unfortunately, contacts has stopped
1. On your Android Device go to Settings.
2. Choose Apps then ALL (by swiping to the right)
3. Locate Google+ and open it.
4. Tap or Click Uninstall Updates and then Select Disable.
Reboot your phone and the contacts should now start working.
One of these methods above should fix this for you. If none of them works, then a reset to factory defaults is needed. Make sure you back up your data to Google by syncing.