when it was new windows 8, this app works fine but after using some months in this app, when i sent messages suddenly it create duplicate message of same text which i sent so what can i do to solve this problem?

Open Store and see if there is any new update, if yes run it and do a update.

Hi,

Based on Cyber_Defend_Teams suggestion, please try the following methods to solve this issue:

Method 1: Run Modern UI App Troubleshooter

Download and run the Modern UI App troubleshooter and check, please refer to the following link:

http://download.microsoft.com/download/F/2/4/F24D0C03-4181-4E5B-A23B-5C3A6B5974E3/apps.diagcab

Method 2: Update your app

Keeping your app up to date is one way to make sure that it keeps working. Youll see a notification in the Store whenever an update is available for your app.

Please review the Update your app in this article What to do if you have problems with an app:

http://windows.microsoft.com/en-US/windows-8/what-troubleshoot-problems-app

Method 3: Sync the App license

If a license for an app is out of sync with the license installed on your PC, the app might stop working.

Please review Sync the App license in this article What to do if you have problems with an app:

http://windows.microsoft.com/en-US/windows-8/what-troubleshoot-problems-app

Method 4: Uninstall and reinstall this app.

1. Right-click on the app in the Start and then click on Uninstall in the bottom.
2. Click on store, and then install the App.

 

For your information, please review this article Messaging app for Windows: Frequently asked questions to get more help.

  

Regards,

Lany Zhang