If your device isn't recognized by PC when plugging via USB cable, try the following actions to recover:
- Check that you are using the original Nokia USB cable and that the cable is properly connected to the phone and PC.
- Disconnect the mobile device and connect it again.
- Remove the battery, insert it back again and restart your mobile device. In phone models with integrated battery, press the power button for around 10 seconds
- Restart your PC.
- Try connecting to another USB port on your PC. Connect the phone directly to your PC instead of connecting e.g. via a USB hub.
- In Symbian devices, try selecting another connection mode in your mobile device (e.g. Nokia Suite/PC Suite, Mass Storage, Media Transfer). Note that when connecting to Nokia Suite, you need to select Nokia Suite/PC Suite mode (check the connection mode in Settings > Connectivity > USB).
- In some Symbian devices, if having copied a large number of files (> 4000 files) in Media Transfer USB mode to the device, the PC connection may not succeed any more. If this happens, try deleting files with File Mgr. application to decrease the number of files below 4000.
- If running Nokia Suite in the PC, check that the latest Nokia Suite version is installed (check for updates in Nokia Suite Software Updates menu). Check also that your phone is compatible with Nokia Suite.
- If Nokia Suite is not able to find your Symbian or S40 phone, try reinstalling Nokia Suite software in your PC.
- If possible, check if your phone can be successfully connected to another PC.
If the above actions don't help, reset the device back to factory settings.
Check also that you have the latest device software version installed in your mobile device.