Cfdir can take a while on a large directory and it seems to blank the screen out while waiting. How can a message like "Please Wait" or a progress bar be put on the screen instead ?
I am not sure how much big your directory is?
Have you tried some thing like this?
<img id="busy" src="busyIcon">
<cfdirectory action="list" directory="E:\" name="myvar" >
<cfdump var="#myvar#" >
code for hide busy icon.
I know this is looking odd but you can try this.