I am using Android 6.0 on C5302 Xperia SP. For some unknown reason, all the contacts in my phone show up twice with a few exceptions. I tried to manually delete the duplicates but that resulted in both the duplicate and the original one getting deleted. I tried out many apps from the play store to merge or delete duplicate contacts but no duplicates were found. Can someone help me out on this.
Under contacts to display option, I just have my google account selected.
*Go to contacts>filter Uncheck everything, then Check the ones under Google tab.
*Go to WhatsApp>Settings>Contacts uncheck "show all contacts".
*Go setting>account>WhatsApp tap the WhatsApp under Account tab and uncheck "Sync
Contacts".
*Go setting>account>then remove Whatsapp.
*Go back to setting> accounts then add Whatsapp, Check "Sync Contacts".
*Go to WhatsApp>Settings>Contacts Check "show all contacts".
That worked for me after playing every kind of settings. Hope works for you too...
Q & A