(Image credit: Toshiba) Try a different USB port or computerįor all their uses, USB ports like to mess with us from time to time, so it helps to troubleshoot the port.ġ. You may also need to press a power button or flip a power switch to an 'On' position, following this. If it does, connect either an external AC power supply (it's recommended to use the one that it originally came with, or one that matches the ratings printed on the enclosure if you don't have the original) or a USB cable to the port, and it should power on. Firstly, check the enclosure of your external hard drive to see if it has more than just a single USB port. While most external hard drives get their power from their single USB port that also provides the data transfer channel, others may require an external power source, such as an AC supply or a secondary USB port.ġ. This may sound like an obvious step to follow, but the simplest faults are often the most common when it come to tech. Check your external hard drive is powered up Read on for detailed instructions regarding each step. Install your hard drive directly into your computer or a new enclosure.Check your drive is enabled and allocated/mounted.Check your external hard drive is powered up.How to fix an external hard drive that's not showing up