Let me try this. Explorer does lock up if a directory or folder has a file it can't handle. That is an enduring bug that MSFT will not correct for reasons discussed in other discussions.

Ok, what to do about it?

Try unregistering explorer's rendering feature. Here's one of hundreds of articles about how -> http://www.virtualdub.org/blog/pivot/entry.php?id=89

shmedia is just one of the many items I've unregistered to get Explorer to stop crashing. There are others but I must not go on and on about it. Let's sum it up.

Explorer will crash if there are files that it can't handle. MSFT has yet to tackle this one except to tell us to move these files out or off the machine or delete the corrupt (according to MSFT).

Now you know. Now you can research this further.
Bob