The Cause of the Bug
When two iPhone users text each other, by default their messages are sent through iMessage, Apple’s free iPhone-to-iPhone messaging tool. You’ll know a text was sent using iMessage because your word balloon in the Messages app is blue. When one person in a conversation has an iPhone and the other person has another kind of phone, for example, an Android, traditional text messaging is used (represented by the green word balloon). The problem happens when someone who previously had an iPhone and used iMessage switches to Android or another platform. In that scenario, the Apple system sometimes fails to recognize that a switch was made and tries to deliver the text using iMessage. Because the iMessage network is separate from the standard text messaging network, the message dead-ends and is never delivered to its recipient. To make matters worse, the sender doesn’t know that the message wasn’t delivered.
Fix the Bug With Apple’s Free Tool
Apple released a free tool that lets former iPhone users unregister their phone numbers from iMessage, which prevents texts sent to them from falling prey to the bug. If you used to be an iPhone user, and switched to Android and aren’t getting some texts, do the following:
Fix the iMessage Bug Before Switching to Android
If you’re planning to switch to Android, but haven’t done so yet, there’s an easier way to prevent the bug from happening. Remove your number from iMessage. This means that you won’t get free iMessages any longer. However, those messages are delivered as text messages so that you don’t miss anything. To do this:
Fix the Bug If You Still Have Your iPhone
If you switched to Android, but haven’t recycled or sold your used iPhone, there’s another way to solve the bug. In that case: