One of the best tools for reading information about a drive, its file system, and mounting/unmounting drives, is the "DISKS" utility, which is usually packaged in every Linux installation, including Zorin OS.
When DISKS is open, you can see the drives on the left side, once clicked, info on them, as well as their partitions, will show on the right. Additionally, you can also see what drives are connected to your computer using this terminal command...
Hold CTR ALT F2 to open terminal.
lsblk
Paste info received in terminal here in your response. But my guess, is that based on the error message you got, this is a permissions related issue. With a little more info, hopefully one of us are able to help you.