Sigil on Mac. Disk drive list

Hi,

This maybe basic but I'm new to Sigil and can't find an answer anywhere.

I'm running Sigil on Mac (Monterey). I have two partitions on my computer. When I try to add files to a project only the main partition (labelled Computer) is showing along with my user folder. I can't get the program to show me the other drive/partition. I've tried the usual reboot, re-install etc by nothing.

Hope this is not too obvious.

Thanks in advance.