From: anil on 12/10/2002
On the Windows taskbar, click the Start button
Type "C:\Program Files\Microsoft Office\Office\Excel.Exe" /Automation (include the quotes) -- adapt to fit your path.
If your error disappears, there is either an add-in or a (hidden) workbook that is loaded upon XL's start, which is causing problems.
Try locating the XLSTART directory, move everything from there.
In XL: Tools, Addins, note the ones checked and uncheck them one at the time, each time restarting XL
In XL, Tools, options, general. Check if a path is entered after "Alternate startup file location". Clear it.
Another option is to open XL in Safe mode:
"C:\Program Files\Microsoft Office\Office\Excel.exe" /Safe
Also, you might try:
"C:\Program Files\Microsoft Office\Office\Excel.exe" / Regserver
Another possible problem is a corruption of your toolbar customisation file:
Locate all files with extension .xlb
Rename the extension(s) to something like .old
Now try and start XL again.
Finally, this is what MS has to say:
XL: How to Troubleshoot Startup Problems in Microsoft Excel (Q280504)