In SharePoint 2013, if you may face this error message “You may receive the following warning dialog box when opening a workbook using Excel Services in SharePoint” when you access excel services.
To suppress this and other warnings from Excel Services,
Navigate to SharePoint Central Administration > Application Management > Service Applications > Manage service applications > Excel Services application > Trusted File Locations and click on the Address that represents the excel sheet
In the External Data section, Please navigate to Warn on Refresh, do the unchecking of Refresh warning enabled and click OK.
Happy SharePointing Folks 🙂