Find a drive in Disk Utility
Summary:
Find a drive in Disk Utility.
Disk Utility is a program that displays connected storage devices. It is a good place to look for problems if a disk is not performing properly.
This program is found by opening the startup disk (usually MacHD or similar) then Applications, then the Utilities folder. Disk Utility will be somewhere in this directory.
Connected disk drives are listed on the left side of the program. If a drive is working as expected, it will appear like this:

Each disk gets one hardware line, and at least one volume line. In this example, a 20 GB disk is listed (20 GB appears as 18.6 in Disk Utility.) This is that drive's hardware line. Underneath and indented from that, there is an entry called "NEW VOLUME". This is the volume line, and anything in that position represents a volume on a drive. This is the same name that appears on the desktop, and can be interacted with using Finder.
If a drive does not show in Finder, there will be something unusual about one of these lines.
In cases of data corruption, the volume line will be:
- Missing, but the hardware line will look normal.
- Showing properly, but is shaded gray instead of the normal color.
- Displaying partition information (like Disk2S4.)
With something physical causing the problem, the hardware line will be affected, instead:
- It will be missing completely.
- It will be missing the size, but say the name of the hardware.