Catalina 10.15 and external hard drive issues

I have an iMac (Reina, 5K, 27" 2017) & I updated to Catalina 10.15. I have my Photos app on an external hard drive & since I updated the OS I can't access the disk correctly. 

When I click on the disk icon I get the following window:

I can't eject the drive. And it ends up freezing the Finder. My only option is to restart my iMac.

The following is what I get when I run FirstAid on Disk Utility:

The external is a Seagate. I’m also using a Seagate for backup. I am not experiencing any issues (that I know of) with that drive. It has done multiple backups since I updated. 

I backup all of my photos to the iCloud. Do I need to erase the external, format & restore Photos?

Any help would be greatly appreciated. Thanks.