In what it thinks is an aid to productivity, Windows 7 (and Vista) will go to these network drives and automatically create a hidden file called thumbs.db which contains a thumbnail image of every media (video or photo) file. Naturally this takes time if you have hundreds of images or some large videos, and I often try to delete the directory before the thumbs.db have finished being created... and get an annoying error message saying that the file can't be deleted as it's still opened by another application.
You can turn off the generation of this file by going:
Start > Run > Gpedit.msc
User Configuration > Administrative Templates > Windows Components > Windows Explorer > Turn off caching of thumbnail pictures in hidden thumbs.db> Enabled
I hope this proves helpful... if it does, please click on an ad to show your appreciation.