properties panel keeps asking to save excel spreadsheet that supplies some of the list items

I have set up a new properties panel that reads in from an excel spreadsheet to provide the lists for a number of drop down boxes.

For some reason, when a part is opened that uses this particular properties template it asks for the excel sheet to be saved each time.  I cannot understand why it is asking to do this as the spreadhseet should only be used to provide the contents of the list and is not used to save any of the selections.

Any ideas?

SolidworksGeneral