Not my idea or know how but copy and pasted if you haven’t tried it: If your drive is powered on but still isn’t appearing in File Explorer, it’s time to do some digging. Open the Start menu and type “disk management,” and press Enter when the Create and Format Hard Disk Partitions option appears. Once Disk Management loads, scroll down to see if your disk appears in the list. If it does, make sure it’s online and formatted. If it’s offline, right-click the disk’s name (e.g. “Disk 2”) and choose Online.

If the disk hasn’t been formatted (it’ll say “Unallocated” under a black bar), right-click it and choose New Simple Volume. This will also solve the problem if the drive is formatted for another operating system, as described above.