The "Unfortunately, contacts has stopped" error prompt has been appearing in different Android devices including a series of Galaxy tabs and smartphones like the Galaxy Note 4. This error is tied to a certain update on the Google+ application with most of those who have encountered it have enabled the Auto Update feature on Google+.
To do so, you have to go to the Google+ app page, tap the Menu icon (three vertical dots), and then remove the checkmark from the Auto Update checkbox.
But if you are having getting the same error message and wouldn't opt to do the aforementioned solutions, you can try the following workarounds first.
1. Clear Cache and Data. Try to clear temporary storage area of your Contacts. Here's how: Go to Settings->Application Manager-> All Tab -> Contacts -> Clear Cache
You may also select Clear Data but please note that choosing this option will erase all your customized data in your Phone app settings. But some users who have tried this method found it helpful and has fixed the problem. Here's how: Open the Phone app->Clear Cache->Clear Data
2. Configure/change Date Format. In some cases, where the error has been tied to an incompatible date format, you can try to configure or change the date format on your device. Here's how: Go to Settings-> More-> Date and Time, and then change the format to 24 hours.
3. Uninstall Faulty Apps. Some users have also found that some rogue apps can also trigger this problem to occur on their device. To help you isolate and determine if this is really the cause, try to enter Safe Mode on your Note 4 and see if the error message still prompts. If it won't, then it's more likely a third-party app that is triggering it to appear. In this case, exit Safe Mode and try to disable or uninstall the most recent app which you suspect is at fault.
4. Perform a Hard Reset. Reset your phone to factory defaults. Again, don't forget to back up all your personal information and contents before you perform a hard reset for they will be erased in the process.
These workarounds have also helped a number of Galaxy device owners including Note 4 who encountered the "Unfortunately Contacts has stopped" error message after getting the Lollipop update.
Hope this helps.
For more problem solutions and troubleshooting guides on Galaxy Note 4, please check out the http://stephaniefulke.blogspot.com /2015/07/Samsung-Galaxy-Note-4-Troubleshooting.html" target="_blank">Troubleshooting Page we purposely created for Samsung Galaxy Note 4 users.