When you open any attachment in Outlook, Outlook needs a location to store the
file--it has to unencode the file into its original format.
Outlook uses the Temporary Internet File folder to hold those files.
You may want to start saving them to your favorite location (rightclick on the
attachment to start this process). Then go to that favorite location and just
open that file from there.
Alternatively, you could open the attachment, but before you do anything, do a
File|SaveAs and point at that favorite location.
If you reopen that attachment in Outlook, you may get lucky and have Outlook
store it in the same location. If it does do that, you may get unlucky in that
this newly saved file could overwrite any changes you've made.
I do this (I'm not sure if it's the easiest way, but it works for me):
Open Internet Explorer
Tools|Internet Options|General Tab
In MSIE 7.0 (just available from MS), I click on the settings button under the
"Browsing History" section.
Then I click on View Files
Then I make sure I'm looking at Details (View|details)
And make sure I can see the last updated date (View|Choose Details)
Then I sort by that date (or by type or by name or by anything that will help me
find the file).
Then I rightclick|copy
and windows explorer, go to that favorite folder and rightclick paste.
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If you wait too long to do this, the file could be overwritten or worse
deleted. (Windows has a limit of how much space will be used for this stuff.)