Right click in the white space in the same directory and choose ' Paste' (this will paste the ' Packages' folder from ' InstallESD.dmg' to the thumb drive.

On the left side of the Finder window, select your thumb drive now called ' OS X Base System'.

Right-click on the folder called ' Packages' and choose ' Copy'.

Quit Disk Utility and close all Finder windows.

Click ' Restore' then ' Erase' (this process will take 5-10 minutes).

Drag the thumb drive partition ' Untitled 1' on the left side of Disk Utility to the ' Destination' field in Disk Utility.

Drag the ' BaseSystem.dmg' file from the ' InstallESD.dmg' Finder window to the ' Source' field in Disk Utility.

Highlight your thumb drive on the left side of Disk Utility.

Open Disk Utility and drag it to the opposite side of your screen so you can see both windows.

Move the resulting Finder window to one side of your screen.

Notice the file called ' BaseSystem.dmg' (grayed out).

Double-click on the ' InstallESD.dmg' file (on your Desktop).

Type ' defaults write AppleShowAllFiles TRUE'.

Open ' Terminal' (Applications > Utilities).

Confirm the change to continue by clicking ' Partition'.

Choose the ' GUID Partition Table' option, then click ' OK'.

From the ' Format' drop-down menu, select ' Mac OS Extended (Journaled)'.

From the ' Partitions Layout' drop-down menu, select ' 1 Partition'.

Warning: the following steps will erase all contents on your thumb drive.

Highlight the thumb drive on the left side of Disk Utility.

Open Disk Utility (Applications > Utilities).

Right-click on your Desktop and choose ' Paste' to put a copy of the file on your Desktop.

Right-click on the file called ' InstallESD.dmg' and choose ' Copy'.

Right-click on the ' Install Mac OS X Yosemite' app and choose ' Show Package Contents'.

Open Finder then click on ' Applications'.

When the download has completed, DO NOT INSTALL.

Open the App Store and begin downloading OS X 10.10 Yosemite ( direct link).

This includes everything you need to create a clean, bootable thumb drive AND proper clean-up afterwards.

If you follow the steps exactly as outlined, total time to completion is 20-30 minutes.

Yosemite os x bootable usb