It is possible for the device drivers to be incompatible with Windows 8.1 due to its age. As a test, I’d recommend confirming if it works with Microsoft Windows 7 first. if it does then the hard drive should be formatted in Windows 7 to NTFS before attempting to connect it again once more to Windows 8.1.
Thank you for your response, I was thinking the same, but hoping there was a workaround to make it work on Windows 8.1 without having to transfer everything to a new drive.