My Drive Is Not Mounting on Mac Terminalby Bennett Gavrish
When you connect an external hard drive or flash drive to an Apple computer, the Mac OS X operating system automatically recognizes the device and mounts its data in the Finder application. If you are having trouble getting drives to successfully mount on your Mac, you can run several commands in the Terminal program to resolve the issue. Terminal is a free utility that comes installed on all Mac computers.
Make sure the external hard drive or flash drive is firmly plugged into a USB or Firewire port on your Mac.
Click on the "Finder" icon in the Dock at the bottom of the screen.
Highlight "Applications" from the left side of the window, open the "Utilities" folder and double-click on the "Terminal" icon.
Type "diskutil list" into the blank command prompt window and press "Return" to view a list of all devices connected to your Mac. Each device will have a name, drive and number listed next to it.
Type "mkdir /Volumes/MyDisk" and replace "MyDisk" with the name of the drive that will not mount. Press the "Return" key.
Type "sudo mount -t hfs -o rdonly /dev/disk0s1 /Volumes/MyDisk" into the window. Replace "disk0" with the drive name, replace "s1" with the device number and replace "MyDisk" with the device name. Press "Return."
Check to see if the drive is now mounted in the Finder. If it is still not showing up, go back to Terminal, type "disktool -r" and press "Return" to refresh all connected drives.