Would help if you mentioned which version of Excel you have.
Different fixes for different versions.
Since you're talking about Autosave, I will assume Excel 2000 because newer
versions don't have Autosave only Autorecovery which is not the same thing.
Office 2000 Autosave had a bug which was corrected in a Service Release.
Try the advice below from Dave Peterson............
Start Dave Peterson text..........................
Maybe...
http://support.microsoft.com/default.aspx?scid=kb;en-us;231117
XL2000: AutoSave Settings Are Not Retained Between
Sessions of Excel 2000
As an alternative, you may want to consider using Jan Karel Pieterse's addin
called AutoSafe (note spelling).
It doesn't overwrite the existing workbook when it saves. It saves to a user
selectable folder. And when it's done, it either deletes these backups (or
puts
them in the recycle bin). And the user can always restore the backups from the
recycle bin.
http://www.jkp-ads.com/Download.htm
(look for AutoSafe.zip, not autosafeVBE.zip, for your purposes.)
End Dave Peterson text...........................................
Gord Dibben Excel MVP
Every time I start Excel anew the autosave reverts to the 10 minute interval,
prompt before saving, default setting. I want, in general, 15 minutes and no
prompt, just do it. It is annoying to always have to renew this setting.
Gord Dibben MS Excel MVP