This is not normal behavior if you really mean you have to use Window|Unhide.

If it happened to me, I'd start excel in Safe mode

close excel
windows start button|Run
excel /safe

File|open a few workbooks to test it out.

If everything worked ok, I'd start looking for "helpful" addins that get loaded
when excel starts normally.

Chip Pearson has some notes on how to diagnose startup errors at:
http://www.cpearson.com/excel/StartupErrors.htm

And Jan Karel Pieterse has more notes at:
http://www.jkp-ads.com/Articles/StartupProblems.asp

========
It is normal that one window gets "hidden" when another window is activated.
But you don't mean that, right?

" wrote:

If I have more than one workbook open, the workbook that I am not on at
the time stays hidden, I need to go to the windows menu to unhide it,
sometimes I forget that the book is open until I exit from excl and it
will ask to save these other open files,
How do I stop these workbooks from hiding???

--

Dave Peterson