I've run into this same issue and clearing the metadata using MS Document Inspector did work on several documents which now pull up instantaneously BUT I've got about 600+ documents in a user's folder that need their metadata cleared. Does anyone know how this can be done easily? And non-painfully, of course.
Incidentally, my issue was extrmemly similar with a 6 year old file server (Win2003) being retired to greener pastures. Only thing to add is that with WinXPP and Office 2007 user has the capability to cancel and there's more troubleshooting information being displayed in the status bar (i.e. "Contacting...." old server). Not the case with Win7P and Office 2007, you can't cancel it and all you see being displayed is "Downloading...." with the annoying blue circle going round and round for minutes on a 65K document.
Thanks in advance.
File Server: Win2008R2
Wkstn: Win7 Pro SP1
MS Office 2007 w/ SP2