If I open an Excel document from the folder it resides in (Desktop, etc.) it can take 5 or more minutes before it opens. If I open the Excel app first, then try to open an Excell doc from it's folder the same thing happens.

However, if I open the Excel app first, then open an Excel doc by selecting open from the Office button (selecting a recently opened one or browsing to the document) it opens normally.

Any ideas?