I am by no means an Excel expert, however, I am very comfortable with all the
basic functions of Excel. From time to time, I've noticed that after opening
an Excel file, working in it, saving, closing, opening it, performing a Save
As, etc. that there are times it does not save all the work. I habitually use
CTRL+S to save while I work and when I close the spreadsheet window, don't
get a Save prompt, so I am extremely confident I'm saving my work just fine.
For example, I worked on and off in a spreadsheet last week, attached it to
an email, but when I opened the file on my PC the next day, some of the
changes were not there. I then went to my Sent folder, found the email,
opened the spreadsheet I had attached and the files were different (correct
in the attachment, but not on the file on my PC).

Any ideas as to why this would happen? I am absolutely certain it is the
same file, so that's not the explanation. Let's assume I had attached the
file when it was open on my desktop, then sent the email with the file
attached, would that account for it? I would think that when I later closed
the file, if there were unsaved changes, it would prompt me to save them,
right?