There's a description of the process in the following MSKB article:

Description of the way that Excel saves files
http://support.microsoft.com/default.aspx?id=814068

Perplexed wrote:
Each time I 'save as' MS Excel saves an additional file in my folder which
has archive properties and also tags it as temporary. I would like to
eliminate this additional file from the saving process. How is this done?


--
Debra Dalgleish
Excel FAQ, Tips & Book List
http://www.contextures.com/tiptech.html