Welcome to the TH Community, @Cerjos!
If the external HDD appears properly on another computer, it's probably best to backup your data there before continuing with the troubleshooting. Indeed, the issue could be coming from the system, especially if you had gone through any recent OS updates. I'd advise you go to Device Manager and
uninstall & reinstall the external as a device from there. If that doesn't help you detect the drive properly afterwards, try re-installing the USB hub controller drivers from the motherboard/computer/laptop manufacturer's official website. There, you should be able to find your model and see all the available drivers & downloads for your current OS version. You could also try plugging it in another USB port on the computer, just to check how it will appear in Disk Management then.
Give it a try and let me know how it goes.
SuperSoph_WD