EXPLAINED… Disk Utility’s interface
1 Connections
Drives connected to your Mac are shown in the sidebar, with volumes beneath.
2 Toolbar
The toolbar has tools for first aid, partitioning, erasing, mounting and unmounting.
3 Information
The main window displays information on the selected volume, like format and capacity.
4 View options
The View Sidebar button allows you to choose to view only volumes, to make the sidebar less confusing.