1. Set whether to turn on the USB debugging function and enter "Settings >"; About this machine (about mobile phone) > version information ",click the version number continuously, and after" You are now in developer mode "appears, enter" Settings >; System settings (other settings) > developer options > USB debugging "to start USB debugging.
2. If the mobile phone can be charged normally and the USB port is normal, it is recommended to plug and unplug the data cable again. Select USB transfer file.
3. If "use USB" is not recognized and "transfer files" is selected, it is recommended that you restart your mobile phone and computer and try to reconnect.
4. I suggest you replace the data cable as much as possible, and ensure that the USB port of the mobile phone and computer is normal, and eliminate the abnormality of the data cable interface or USB interface.
5. If the mobile phone driver software is installed on the computer (non-Apple computer), a new device prompt appears when connecting to the computer, which is generally a driver problem. I suggest you try reinstalling the driver.
6. Restore the factory settings after backing up the data and try again.
If the above methods fail to solve your problem, you can go to the nearest official service center of OPPO and have it tested by professional engineers.