No solution was found after searching the web although there are similar issues out there like:

http://www.virtualbox.org/ticket/7462

http://www.virtualbox.org/ticket/1776

I was almost ready to give up when I found page 142 on the Virtual Box manual. Section 9.7.1 tells how to configure a physical disk to be accessed as if it was attached to the guest/virtual machine.

So the guest OS instead of accessing the disk using the USB bus it would access using the SATA or IDE bus.

There’s a warning on that page that I’m copying here:

Warning: Raw hard disk access is for expert users only. Incorrect use or use of an outdated configuration can lead to total loss of data on the physical disk. Most impor- tantly, do not attempt to boot the partition with the currently running host operating system in a guest. This will lead to severe data corruption.

Following the instructions on that section I could access my external USB drive successfully.

This is what I did, remember that I’m using OSX as host operation system.

Connected my usb drive. OSX automatically mounts it.

Opened a terminal and wrote mount to find which /dev device is the disk mapped to. It was /dev/disk1s1:

$ mount
/dev/disk0s2 on / (hfs, local, journaled)
devfs on /dev (devfs, local, nobrowse)
map -hosts on /net (autofs, nosuid, automounted, nobrowse)
map auto_home on /home (autofs, automounted, nobrowse)
/dev/disk0s3 on /Volumes/BOOTCAMP (ntfs, local, read-only, noowners)
/dev/disk1s1 on /Volumes/SergioDrive (exfat, local, nodev, nosuid, noowners)

Now before using it on virtual box I unmounted it on OSX:

$ diskutil unmount /Volumes/SergioDrive
/Volume SergioDrive on disk1s1 unmounted

Now I created the virtual box image file that I’ll use to configure my virtual machine:

$ VBoxManage internalcommands createrawvmdk -filename ~/VBAccessToSergioDrive.vmdk -rawdisk /dev/disk1s1
RAW host disk access VMDK file /Users/machados/VBAccessToSergioDrive.vmdk created successfully.

Now you can use the virtual box gui to add the image file as a disk to the virtual machine. This is done under the storage definitions. I added another disk under SATA controller.

This can also be done on the command line with this command:

$ VBoxManage storageattach "Windows 7" --storagectl "SATA Controller" --port 1 --device 0 --type hdd --medium ~/VBAccessToSergioDrive.vmdk

The command has no output. Of course “Windows 7″ is the name of my virtual machine.

This image file can only be used with the same physical external disk because it maps the UUID of the disk.

Note that when the usb storage device becomes available to the guest operating system, it becomes unavailable to the host operating system. So you should save and close any file/document open from the same storage device.

Before you start, make sure the guest virtual machine is stopped and logout from VMWare server.

Start by finding the vendor id and product id of the storage device. The best way to do this is to open the latest vmware log file. It is located in the same directory where the vmx files for the guest virtual machine are.

Once you have the latest vmware log file open, search for the string “USB: Found device” without the quotes.

You’ll find something similar to:

Sep 03 14:14:35.759: vmx| USB: Found device [name:Wacom\ USB\ Composite\ Device vid:056a pid:00d1 path:1/0/2 speed:full family:hid,hid-bootable]

Sep 03 14:14:35.759: vmx| USB: Found device [name:Seagate\ RSS\ USB\ Mass\ Storage\ Device vid:0bc2 pid:2100 path:1/1/1 speed:high family:storage]

Sep 03 14:14:35.759: vmx| USB: Found device [name:Realtek\ RTL8187\ Wireless\ 802.11b/g\ 54Mbps\ USB\ 2.0\ Network\ Adapter vid:0bda pid:8187 path:1/1/9 speed:high family:other]

From that listing you should be able to locate your usb storage device. Once you have found it, copy the vid and pid values from the respective line. For example:

vid:0bc2 pid:2100

Now, run notepad as administrator (right click on the Notepad icon found in Start > All Programs > Accessories menu and select ‘Run as Administrator’).

Click ‘Yes’ on the security question to allow Notepad to be run as administrator.

Now press Ctrl+O to open the vmx configuration file. On the lower right corner of the Open File dialog there is a combo box where, by default, “Text Documents (*.txt)” will be selected. Change that to “All Files (*.*)”.

Now locate the directory were your guest machine configuration files are (likely to be under C:\Virtual Machines) and open the file with .vmx extension.

Scroll down to the bottom of the file and enter the following on a new line (replace the contents within quotes with your vendor and product id found above):

usb.autoConnect.device0="vid:0bc2 pid:2100"

Save and close the file.

Now start your guest virtual machine. If you are using Ubuntu 10.04 your USB device will be automatically shown on your desktop.

You’ll also notice that a notification on Windows 7 will show up notifying you that a device driver for vmware was installed successfully.

To be able to enjoy seamless integration between the host operating system and the VirtualBox guest you have to install VirtualBox Additional Tools on the guest operating system.

To do so, follow the steps:

Ensure you have a working Internet connection.

Step 1:

Install requirements for the Additional Tools:

sudo apt-get install gcc linux-source-virtual linux-headers-virtual dkms

Reboot after installation.

Step 2:

After logging in again find the Install Additional Tools option on the Devices menu.

Then on your guest mount the cdrom:

sudo mount /media/cdrom

Step 3:

Now install the tools:

cd /media/cdrom
./VBoxLinuxAdditions-x86.run

This will install the additional tools for virtual box.

Reboot your system and you’re all set.