"Brian Tillman" wrote in :

VanguardLH wrote:

If the OP has been
using Word for several months, or longer, then they should've been
quite aware of what were the filetypes being generated by the older
version of Word.

Not necessarily. If the OP is using Vista's default config, known file
types are hidden, so they might not know they've switched to .docx files.

The filetype remains hidden when shown as an attachment in Outlook?