1. Check whether the storage space is enough. Please go to settings > storage space and check whether the remaining internal storage space is larger than the storage space needed to download the application. If there is not enough storage space during the installation, try to clean up the application, free up the storage space needed to download the application, and then reinstall.

2. Turn on the unknown source application download switch. If the application is not downloaded from the application market (such as QQ browser, Baidu browser and Chrome browser), please do the following:

Before EMUI 8. X: Go to Settings, search for application downloads from unknown sources, and turn on this switch.

EMUI 9。 X & ampEMUI 10。 X & ampEMUI 1 1。 X & Magic UI 2. X /3。 X/4.0: Enter Settings, search for external source application downloads, and turn on this switch. At the same time, when installing a foreign application, find the corresponding browser, turn on the switch, and install other applications in the application.

3. Restart the phone. Switching to other interfaces when installing an application downloaded from a non-application market will cause the installation to stop. It is recommended to restart the mobile phone to release the occupied space and try to avoid quitting the installation interface halfway.

4. Device Manager closes the active application. If you are prompted "Security policy prohibits the installation of applications from this installation source", open the settings, search the device manager, and close the activated applications.

5. Download the installation package from official channels. If the prompt "Installation analysis failed, no signature, abnormal signature, inconsistent signature, attempt to modify system files" pops up during installation, it is recommended to obtain a reliable installation package from official channels.

6. Check whether the third-party housekeeper software is installed. Please check whether the third-party housekeeper software (such as 360/ Tencent Butler) is installed. If yes, please try to uninstall this software and try again to avoid conflicts caused by multiple housekeeper applications running at the same time.

7. Delete the "application market" data. If the application market cannot be installed after downloading, it is recommended to delete the data of the application market and try to reinstall it. Operation path: enter settings, search application management, find application market, and click storage > delete data.

If the above methods fail to solve the problem, please back up the data in advance (WeChat /QQ and other applications need to be backed up separately) and bring the purchase voucher to Huawei Customer Service Center for testing and processing.