If the Toshiba hard drive is still not working, try to update the device driver. An outdated or corrupted hard drive driver will cause some problems while using the device. Since your hard drive is not detected by the PC, you cannot update the driver via Device Manager. Go to the official site of Toshiba, then download and install the latest driver by entering your model or the serial number of your disk.
A Toshiba external hard drive that is not working in such a case may be caused by a problematic device driver or a drive letter conflict between your Toshiba external disk and the partition on your computer. The solutions are easy: 1e1e36bf2d