I am opening excel with the dock icon. I did commnand I on those files that I get the messages about, and each says it will open with word. Each one of those IS a word doc, and I wan them to remain word docs. For some reason excel thinks it has to try and open them.

I am using the excel icon in the dock. Even if start excel by clicking on any excel file, it still shows all those invalid file format message windows when the excel starts up. command I has "open with word" for those files in question...which it should do since they ARE word files. For some reason excel wants to open them upon start up.

Does starting Word and opening a .doc file from Word make any difference?

Have you tried rebooting?
Create new user? Does issue continue there too?

First apologies for posting twice- still learning the forum...
Word works just fine. Rebooting makes no diff either. New user, haven't tried that yet. It's only a few specific word docs that excel tries to open, not all of them. Must be some common denominator with THOSE particular files.

If these files do not contain private info you could post them here to see if we have issues opening them.

eeeggh...unfortunately everyone of them does have confidential info. Any other ideas??

Create a new user account and try opening the file there to see what happens.

Doesn't happen with new user. Seems OK with a fresh start.

You might have a Macro virus. Look for the normal.dot file and see if it was modified recently.

I cannot fiind normal.dot . I searched using command f. IUs there another way to find it? What is a macro virus anyway? Thanks

Look in the Templates folder inside the Microsoft Office folder for a file called "Normal.dot"

It's a long shot, since you say that it isn't happening with a new user, but it's still possible that you have a macro virus. Macros are scripts that run in Microsoft Office applications. Since the macros can run on any platform that runs Office, macro viruses are platform independent, to a degree. Virus writers have taken advantage of Office in the past, but not so much any more since Microsoft got around to turning off Macros by default.

Please clarify your current situation. Does your "seems ok" indicate that there is no longer a problem?

The problem (invalid file format message windows upon opening excel) still exists with MY account, it does not occur with a new user account. I found the normal file, and it appears it was modified recently. What do you suggest I do next? This little problem doesn't prevent me from using excel, it's just an annoting little thing I'd like to get rid of. Of course, I'd like to understand WHY it's occuring. Always like learning new stuff about how my computer works. Thanks

Since that file isn't normally modified unless by a macro, there is a good chance you've got a macro virus. I suggest that you download ClamXav, update the virus definitions, then scan all Microsoft Office files on your system. That includes everything in the Microsoft Office folder as well as all your documents.

http://www.macupdate.com/info.php/id/15850

Edit: That you're getting the error makes sense in a way. If you do have a macro virus, it's probably trying to do something that would work in Windows, but for some reason doesn't on the Mac.

No viruses found with ClamXav. Hmph.

It could be a legitimate macro that's got a bug. Try removing the normal.dot file. You can just drop it on your desktop if you don't want to delete it. A new one will be recreated when you open Office.

I dragged the normal.dot file to the desktop. Opened excel and the same message windows pop up ( same 4 files every time)

After you open the file, if you go to Tools:Macro:Macros... in Excel, do any macros show up in the resulting window?

generic answer for user-specific problems
 

Since this problem is so specific, you should be able to track down what is causing it. But in case you get desperate, I give you my generic procedure for solving user-specific problems.
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You have determined that the problem is only with the one user account.
The problem thus is almost certainly due to something under your home folder.
And it likely is something under ~/Library
( ~ = your home folder)
The most likely thing is a bad preference file under ~/Library/Preferences
You could start by removing the preference files for the apps you are having trouble with.
If the problem persists, you need to narrow the problem down - you could start by moving (via drag & drop) the whole "Preferences" folder that is under ~/Library to the Desktop, then log out and log in again. A default copy of the Preferences folder will have been recreated. Does that improve things? If so, you could use a divide & conquer approach to figure out which of the preference files is causing the problem - move half of the preference files back into the Preferences folder, log out & in again, etc.

If the problem persists, try the same thing with the other sub-folders of ~/Library. E.g. with ~/Library/Caches, ~/Library/InputManagers, ~/Library/Fonts, ~/Library/PreferencePanes, ~/Library/Application Support, ~/Library/Application Enhancers, contents of ~/Desktop, etc.
Also remove any files owned by your user in /Library/Caches (the Library folder at the top-level of the drive)

I trashed the file named "excel setttings" in library/preferences/excel, and that did the trick. Thank you!