My Google Nexus 10 shows the correct time but the stock clock app seems to stop working suddenly. It starts displaying "unfortunately, Clock has stopped" error message with "report it" or OK button and keep crashing after I go to create other user for my wife and add a clock widget. My Nexus 7 updated to Android 4.2.1 also get the same issues when I touch the Clock app. Tap Settings > apps > all apps > clock > clear cache and data, but not working.
How to fix Unfortunately, Clock has stopped issues on android device
* If you don't need the clock app, removing clock widget from all accounts should solve the problem.
* Getting rid of the old alarm clock database by doing these steps:
* Open the Terminal Emulator and run the commands:
# cd /data/data/com.android.deskclock/databases
# mv alarms.db alarms.db.bak