My Passport impossible to remount after wrong maneuver

Hello everyone,

I’ll try to explain my situation as succinctly as possible. My mother got me a MyPassport external hard drive last year for my birthday. She got the one for PC instead of Mac by mistake, but at the time I managed to still use it on my Macbook Air somehow (I do not remember what I did unfortunately), and throughout the past year I did sporadic backups with Time Machine without any issues. Today, I wanted to do another backup since it had been a long time, so I did the usual thing, but the download kept only saying “Preparing” for several minutes, which never happened before. I got impatient and I looked up online at ways to back up on a hard drive without using Time Machine.
WikiHow suggested to reboot my Macbook and get to the Restore page, so I could restore my external hard drive by copying all the files from my Macbook on it (basically doing a new backup). I tried to, but I got an error message, so I just reopened my computer to try to figure something else. But when I went back on my Finder, my MyPassport did not appear despite being plugged in. I went in Disk Utility, and it appears, completely empty, except for a couple hundred mega octets with the notice “2 unmounted”. When I click on “Mount”, nothing happens - no new pop-up window, nothing. When I run a First Aid analysis, everything comes out fine.
I’m not looking to retrieve my previous backups because my computer hasn’t had any crash since I have the hard drive - I’d just like to know what I can do to be able to use my hard drive again. I don’t think my guarantee works anymore, so I’d really like to be able to still use it somehow!
I’m running on High Sierra, if this is of any help.
Do not hesitate if you need more info from me in order to help!

thank you so much

louis

If data in drive is not important, you can reformat your My Passport drive in MacOS Extended Journaled or HFS+ file format which is supported by Mac High Sierra. You can follow below mentioned KBA for further assistance.