(1) Do not use the X in the upper right corner of the Excel window to close the program. Instead use either File Close or Quit Program within the RealData menu (ie. REIA Menu > Quit Program)
or
(2) The free Google Desktop Search software is known to cause Excel-related issues. This issue is documented here:
http://www.excelforum.com/archive/index.php/t-278057.html
Uninstalling the Google Desktop Search program will solve the problem. We are not aware of any workaround to resolve this issue.
or
(3) The Adobe COM add-in for Excel is known to cause Excel issues including this password request. See: http://www.excelguru.ca/
We recommend that you disable the COM add-in within Excel to resolve this issue. We are happy to assist you with this.