"“Seagate Exp” can’t be opened because the original item can’t be found" error with MacBook Air

So I had a very frustrating day today. I copied files from another desktop mac I had onto my 1TB seagate external HDD, and intended to put them onto my Macbook Air. Suddenly, the Seagate external HDD didn't show up on the desktop like external drives usually do, so I found two devices in the finder browser, "Seagate exp" and "Remote Disc".

Trying to open the Remote Disc was fruitless. Opening the External HDD gave me the message "“Seagate Exp” can’t be opened because the original item can’t be found". There was no option to eject the device and when I selected "eject" on the Remote Disc, nothing happened.

I pulled out the HDD, and suddenly got the message "Seagate was not ejected correctly" or whatever. What? So it did notice the hard drive? Then I tried searching for a driver to download for Seagate because I thought maybe that was the problem. I downloaded "Paragon NTFS for Mac 15", a universal driver from the Seagate website, but as soon as I opened the Disc Image for THAT, the Installer refused to open! No bouncy symbol in the dock, no new row in Activity Monitor, nothing.

So I'm stuck with a HDD that can't be ejected properly, can't be opened and a driver Installer that refuses to open.

The Seagate hard drive works perfectly fine with the Desktop Mac.

I'm using a MacBook Air running 10.13.1

Does anyone know what I can do?

EDIT: I don't think the remote disc has anything to do with it, sorry about that.