If your iPhone is bothering you with duplicate message notifications for every received iMessage and SMS Text message, the most likely reason is due to “Repeat Alerts” setting being active or being enabled on your device.
In addition to this, the problem of duplicate and even multiple message alerts can be caused due to iOS bugs, iMessage sync issues, iPhone sending alerts to both phone number & Apple ID, Messages in iCloud settings, Duplicate message threads and messages being resent due to network connectivity issues.
Duplicate Message Alerts on iPhone
In most cases, the annoying problem of Duplicate & Multiple Message Alerts can be fixed by going to “Customize Notifications” tab on iPhone Settings, which provides the option to set the number of times that you want your device to provide you with message alerts.
If this does not help, you should be able to fix the problem using other troubleshooting steps as provided below in this guide.
1. Change Repeat Alert Setting
As mentioned above, the problem could simply be due to your device being set to provide repeat alerts for the same message.
1. Go to Settings > Notifications > Messages > scroll down and tap on Customize Notifications tab.
2. On the next screen, tap on Repeat Alers.
3. On “Repeat Alerts” screen, select the None option.
Note: Do not make the mistake of selecting the “Once” option. It will simply result in the notifications being repeated once.
Hopefully, you should no longer find your device bothering you with duplicate message alerts. If the problem persists, move to the next troubleshooting steps.
2. Restart iPhone & Install Updates
Restart your device to rule out the possibility of the problem being caused due to temporary glitches and see if Apple has released an update/patch to fix this issue.
1. Go to Settings > General > Shut Down > Use the Slider to power-off your device
2. After 30 seconds restart your device by using its Power button.
3. After the phone restarts, go to Settings > General > Software Updates.
Tap on Update Now, if an update is available & follow the instructions to update your device.
3. Switch iMessage OFF/ON
While Apple’s iMessaging system works well most of the times, it is also known to suffer from glitches.
1. Go to Settings > Apps > Messages.
2. On the next screen, switch off iMessage by moving the toggle to OFF position.
3. After 30 seconds > eable iMessage by moving the slider to ON position.
4. Check Send & Receive Settings
As mentioned above, the problem could be due to iPhone sending Message alerts to both your phone number and Apple ID.
1. Go to Settings > Apps > Messages > scroll down and tap on Send & Receive option.
2. On the next screen, make sure that only your Phone Number is checked or selected under “YOU CAN RECEIVE iMESSAGES TO AND REPLY FROM” Section.
Having both Phone Number and Email Address being selected can lead to iPhone sending Message Alerts to both f Duplicate Message Alerts on iPhone.
5. Disable Text Message Forwarding
If the same Apple ID is being used for multiple devices (iPhone, iPad & Mac), make sure that the problem is not being caused due to messges being forwarded from other devices.
1. Go to Settings > Apps > Messages.
2. On the Messages screen, scroll down and tap on Text Message Forwarding.
3. On the next screen, switch of other devices & see if this helps in fixing the issue.