It is either an add-in or a (hidden) workbook that is
Loaded upon XL's start, which is causing problems.
Tools-Addins and uncheck all Addins.
Write down which ones were selected.
Now close Excel and then reopen.
If it is working then one of the Addins was causing the problem.
Add them back one at a time, closing and opening Excel each time until you find it.
If this didn't stop the problem, then the problem is a file in your xlStart directory.
Any file in there Is loaded when you start Excel.
Remove the files out of that folder and open Excel to see if the problem is gone.
If it is then add them back one at a time, closing and opening Excel each time until you find it
Regards Ron de Bruin