There are a lot of how-to guides on the internet to create a bootable Windows7 USB drive.
Unfortunately you can’t boot such a USB stick out of the box fromVMware Fusion on Mac OS X.
But there are workarounds to get the USB based Operating System booting in Fusion.
I’m currently using version VMware Fusion Version 3.1.1.
The “Getting Started” screen doesn’t show any option to boot from a USB stick.
The idea is to download a small but effective operating system for the sole purpose of booting from the USB drive. The Plop Bootmanager is the ideal tool for this exercise. Linux based, small and effective.
Download the latest version from above website and unpack it. You will get a new folder plpbt-x.x.x (x depending on the version you downloaded). We are only interested in the iso-image of this boot manager. This particular file is called plpbt.iso.
Let’s now go back to our VMware and create a new virtual machine (File/New…).
Click “Continue without disc”.
Check now the radio button next to “Use operating system installation disc image file:”
in the new popup window you need to select the previously downloaded and unpacked plpbt.iso file.
Your screen should now look as follows:
Click “continue” for progressing with the installation of the boot manager.
The next screen is asking you for the right Operating System type and its version. We are choosing “Microsoft Windows” and “Windows 7″. Even though the boot manager itself is based on Linux the operating system we want to boot is MS. The good thing with Plop is that it works in such a virtual machine basically configured for another type of guest system.
Please click once more “continue”.
Click on “Customize Settings” and choose a name for your new Virtual Machine. We are using in this example: Boot_Manager.vmwarevm
Click on “Save”.
The next screen shows you different options for fine tuning your virtual machine. We leave everything as it is, but click just for reasons of illustration on “USB Devices”. As the following screenshot shows, the virtual machine must be running before you can add USB devices. What VMware Fusion doesn’t tell you however is that you need to connect the USB device you want to boot later. So let’s do this first now, start/connect your bootable USB device.
Now we are starting our Boot Manager Virtual Machine by clicking on the green “Start Up” button. After a few seconds you will see the following screen, but don’t try to scroll down to “USB”, as your device would not be found.
Click first on “Settings” and then on “USB Devices”. This will show you a screen, similar to the following one – depending on your equipment.
In our case the “ChipsBnk ThinkPad Secure Hard Drive” is the device we want to boot from. Please ensure that the checkbox next to it is ticked and that the column “Plug In Action” reads “Connect to Windows”. Now we are done and can close this window.
We only have to reboot our virtual machine by sending a “Ctrl-Alt-Del” (or similar ways). We have to choose“USB” in the Boot-Manager followed by pressing “enter” and off we go to boot our USB based Operating System in a virtual machine.
We can see that the Operating System on the USB stick is now booting:
After a couple of minutes you should be able to work with your booted Operating System. Please don’t install the VMware Tools, in case you want to boot later again natively outside of any virtual environment.
Source Jeannot Muller’s blog