Check if your PC has installed iTunes. if yes, try to restart your iOS device and import again.

1. If the problem persists after restarting, you may try to fix the media library. (Launch 3uTools -> Files -> File System (User) -> right click iTunes_Control -> Delete.

(Note: All the ringtones and music of your iOS device will be empty after you delete iTunes_Control file)

2. Restart your iOS device -> connect it with iTunes -> select Set up as new iPhone -> Continue -> don’t select Automatically sync when this iPhone is connected, then try to import music /ringtone/video with 3uTools again.

(Note: select Set up as new iPhone won’t delete the important data of your iOS device)