The classic instruction set for mounting a shared folder between a windows host and a linux guest, found here, works as advertised except for one small detail. If your host is a windows7 install, you must define the shared folder in Virtualbox BEFORE starting the guest OS. If, like me, you define the shared folder while the guest OS is running, the shared folder definition will be placed under the “transient folders” section of the definitions, not the “machine folders” section which is where it needs to be. The trouble starts when you try to mount the shared folder. You’ll get the error:
“/sbin/mount.vboxsf: mounting failed with the error: No such device”
Shut down the guest OS, add the shared folder to the virtual machine’s definition, and then you’re good to go.