Solution：
1. Unlock the phone and reconnect to the computer in the bright screen state. Try not to let the screen off during the connection process, so that you can view or transfer files without interruption;
2. Try to replace the USB data cable and replace the USB interface;
3. Android 7.1 and above models have added a file encryption mechanism. New files (such as photos just taken or files just received) cannot be viewed on the computer immediately because they are being encrypted. It is recommended to try at another time period;
4. If none of the above can be solved, try to transfer in other ways, such as FTP.
1. Unlock the phone and reconnect to the computer in the bright screen state. Try not to let the screen off during the connection process, so that you can view or transfer files without interruption;
2. Try to replace the USB data cable and replace the USB interface;
3. Android 7.1 and above models have added a file encryption mechanism. New files (such as photos just taken or files just received) cannot be viewed on the computer immediately because they are being encrypted. It is recommended to try at another time period;
4. If none of the above can be solved, try to transfer in other ways, such as FTP.