Actually, I found a step-by-step (for Windows 7 at least):
1.Open Control Panel
2.Open System and Security
3.Open HP Client Security
4.In the third column, select device permissions.
5.There will be an icon titled "change" on the top right of the Access column, click it.
6.Click yes on the pop up window
7.On the access drop down menu adjacent to "Removable Storage (ex. USB drives)", click "allow - full access"