WhatsApp not Working: Fix
Every now and again, WhatsApp stops working correctly on your iPhone. Here’s a fix you can try, which is derived from a rather widespread issue that once occurred with the developer beta of WhatsApp but is still applicable in some cases.
The issue presents itself in the form of WhatsApp quitting unexpectedly and throwing you back to the Home Screen of your iPhone. This is also called a WhatsApp crash and is fortunately fixable by going through your chats and following a sequence of steps.
Warning: This fix will remove all of the messages that were exchanged between you and the affected contacts. If you require access to the chat logs, your best bet is to ask the other person if he or she can still access the conversation and send it to you as a backup first.
How to fix WhatsApp crashes on iPhone
We will need to clear the chat history for each contact which produces a crash. First of all, check if all of your contacts produce a crash by going to the “Chats” tab in WhatsApp and tapping a selection of friends, one after another. If all of them produce a crash, it is probably being caused by some other bug. If only some of them cause the app to close by itself, jot down the names of those affected contacts.
Open up your “WhatsApp” application once more, this time going to the “Favorites” tab (second image) and tapping the blue “i” symbol next to a problematic contact. Then select “Clear Chat” to wipe your message history with this specific person.
You should now be able to access this contact in the “Chats” window again, this time without a crash. Go through the rest of your list of problematic contacts and repeat the steps to clear the message history for each buggy contact.