If you’re an android users, doesn’t matter on a tablet or phone pda or any android devices, and get this error message pops up constantly “android.process.acore has stopped unexpectedly. please try again” you are not alone, many people owners have same problem, and yes it’s fixable and easy, just need to go through steps below.

Here is an answer that worked for me- from
http://freedune.wordpress.com/2011/03/26/non-lethal-solution-for-android-process-acore-crash/

The problem was occurring due to contact syncing conflicts, the solution also lay in contact management rather than identity management. I took the following steps:
Go offline
Go to Settings > Applications > All > Google Services Framework, hit Force Stop
Go back a level, go to Gmail, hit Force Stop and Clear Data
Go back a level, go to Contacts, hit Force Stop and Clear Data
Go back a level, go to Contacts Storage, hit Force Stop and Clear Data
Repeat steps 2, 4 and 5 for good measure
Reboot, just to be safe
After rebooting and going online, I restarted Gmail, and it started downloading my mail again. I have stopped getting the android.process.acore error now, and still have all my applications.