Not Recognising The External Hard Drive

I bought a 1 TB external hard drive. I used it and always safely ejected it, but now my computer won’t recognise the hard drive. Is their a way to retrieve the files on the hard drive without formatting it on Mac or Windows?

Hi and welcome to the WD community.

See if your hard drive is recognized on the Disk Management on Windows or the Disk Utility app for Mac. Check the link below for the steps. If the external hard drive is recognized, you should be able to use a data recovery program to recover your data, using Google you can find several options. 

How to access Disk Management in Windows 7, Vista, XP or 2000 to manage your hard drives

How to access Disk Utility on a Mac computer