Windows Briefcase in Windows Vista
Windows Briefcase is a tool that used for synchronizing files between computers or removable media. Though Briefcase is being phased out in favor of the Windows Sync Center, it is still available in all versions of Vista. To create a Briefcase in Windows Vista, you simply go into the folder that contains the files required, right-click a blank space in the Explorer pane, and choose New > Briefcase. From there, you can copy the Briefcase to a laptop and then work with the files on either computer. When a file changes, synchronize the Briefcase by right-clicking the Briefcase folder and choosing Update All.
Briefcase cannot be Opened because Disk in Inaccessible Error
Unfortunately, errors do occur when using Briefcase as you have just discovered. The "Briefcase cannot be opened because the disk is inaccessible" error is most often associated with a missing shortcut. If you are receiving this error, let's first make sure that you aren't trying to access the Briefcase via a shortcut. For example, if you normally click a shortcut on your Desktop to open the file, the shortcut could be incorrect. Try opening the file directly from its source location. If the Briefcase opens from the source, then you'll need to delete the shortcut and create a new one.
This same error occurs when using the "Send to" command. This happens when the shortcut to the briefcase doesn't point to an existing Briefcase or the original Briefcase has been moved or renamed. You can change this by going to C:\Windows\SendTo and right-clicking the Briefcase shortcut. Choose Properties > Shortcut and change the target so that it refers to an existing Briefcase.
If you are trying to open the Briefcase from a USB stick, CD, or some other portable storage media, try dragging the Briefcase file from the media directly onto your Vista Desktop. From there, try opening it directly from the Desktop. This technique has worked for other users.