@Yullow: I'm sorry to hear that you have experienced this issue with your Galaxy Tab S4. When connecting to Smart Switch on your PC, are you using the original USB cable that came packaged with the device? If so, can you try a different USB port on the PC, or an alternate USB cable, to see if this helps? Also, is the tablet powered on, and showing the error on screen when you attempt the connection?
If you're unable to complete the Emergency Recovery via Smart switch, then please reach out to the relevant support team in your region by heading to samsung.com > Scroll to the bottom of the page > Contact us, and an advisor can arrange for the device to be inspected and repaired. If it is over 24 months old, or if the issue is deemed to be the result of physical/liquid damage, o ran unauthorised modification, then a charge will be applicable to cover the cost of the service and any necessary repairs.
