Under Snow Leopard, formatting as “Mac OS Extended (Journaled)” appears to select the “GUID Partition Table” scheme by default.

In the bottom pane, check that the “Partition Map Scheme” is set to “GUID Partition Table” (which means it is Mac OS X bootable).

Once the format completes, make sure that the USB flash drive is selected in the left-hand pane.

This format operation will take less than a minute to complete.

Click the “Erase…” button and then the “Erase” button.

Click on the “Erase” tab, select “Mac OS Extended (Journaled)” for “Format” and input a name like “Snow Leopard Install USB” (or anything because this will be overwritten later).

On the left-hand pane, select the USB drive (not the FAT32 or other partition under it).

Format it as a Mac OS X bootable drive by following these steps: The DMG file creation can take 20 minutes or longer.įormat USB Flash Drive as Mac OS X Bootable Leave the defaults of “compressed” for “Image Format” and “none” for “Encryption”.

Select the location to save the DMG file (“Mac OS X Install DVD.dmg”) to.

Click on the “New Image” icon, located in toolbar at the top.

On the left-hand pane, select the “Mac OS X Install DVD” by clicking on it.

If you don’t see the “Mac OS X Install DVD” even after waiting for a while, try closing and starting the “Disk Utility” application again.

A “Mac OS X Install DVD” disk icon will also appear on the desktop.

On the left-hand pane, you will see “Mac OS X Install DVD” appear under the DVD drive when the DVD is mounted.

Run the “Disk Utility” application (under the “Applications/Utilities” folder).

Insert the Snow Leopard 10.6 “Mac OS X Install DVD” disk into the DVD drive.

I just wanted a DMG file for speed and convenience in case I need to clone to a dual-layer DVD or to another USB flash drive. You can skip creating a DMG (Disk iMaGe) file if you clone directly from the Snow Leopard “Mac OS X Install DVD” disk to the USB flash drive. If you want to boot the USB flash drive on a PowerPC-based Mac, please see the comments. The resulting USB flash drive will boot on Intel-based Macs only. Note: I’m doing the following on a Macbook running Snow Leopard. And the USB flash drive is more portable and robust than a DVD. I can use it with a Macbook Air or Pro Retina which do not come with a DVD drive. It would be faster than reading from a DVD. I thought it would be useful to put the Mac OS X 10.6 Snow Leopard installer on a USB flash drive. The instructions below will not work for Mac OS X 10.7 Lion or later versions. Update: Go to Bootable USB Flash Drive to Install Mac OS X 10.10 Yosemite if you want to install Mac OS X 10.9 Mavericks or Mac OS X 10.10 Yosemite instead.

Mac os x snow leopard usb