1 TB External Hard Drive Not Showing Files in Finder

Hi all!

I have an early 2011 MacBook Pro and it recently updated to MacOS High Sierra Version 10.13.6 overnight the other night. I had my 1 TB Seagate external hard drive still plugged into the computer and when my MacBook rebooted it seems to have caused an error with the external hard drive.

When I plug in the external hard drive now, it will show in the Finder sidebar but it appears to be empty when in fact it is about half full. If I open Disk Utility, it is able to recognize the drive and show me there are files on it still. However, I am not able to see these files. I've attempted to run First Aid in Disk Utility but I get an error message that it cannot unmount the disk. I've also attempted to manually unmount the disk through Terminal and also receive a time-out error there.

The external hard drive will also disconnect about 10-15 minutes after being plugged into my MacBook and I'll receive the pop-up error message that the disk was not ejected properly even though I hadn't tried to eject it or unplug it.

Has anyone encountered anything like this before and have suggestions on how to fix this issue?

Thanks!