Hey Rob,
Along those same lines, I just installed Vegas 12 a couple of weeks ago and everything was working fine until the Vegas Explorer window suddenly stopped showing files in any folders in my Windows 7 file tree. All of the folders and subfolders are there, but the Vegas Pro 12 Explorer window cannot show the files that are contained in any of those folders! These are files that I created in Vegas 12.
Could I have unchecked something that shows the content of folders, for I cannot find any reference to this problem in Help or online. Let me know for at this point, the only way I can find the audio files, video MTS or MOV clips, .veg files, Sound Forge takes, or the video logos I created is by going outside of Vegas to copy and paste them onto the timeline from Windows Explorer. Perhaps I am missing something here, but this sudden issue is really strange. Paul