To stop Excel from automatically updating, you have several options:
On PC, you can unlink the add-in from the Intrinio section of the ribbon.
On Mac and PC, you can change your Excel settings to NOT auto-calculate formulas.
On Mac and PC, you can use the find/replace all functionality to add a symbol in front of all of you = signs. This will prevent Excel from recognizing the formulas until you replace all of the symbols.
These options are not as convenient as Intrinio would like and future versions of the add-in will have a more user friendly way to prevent a spreadsheet from updating.
For more information on API calls, check out this article.