Sometime in SharePoint you will get excel work book gave warning message like below:
This workbook contains one or more queries that refresh external data. A malicious user can design a query to access confidential information and distribute it to other users or perform other harmful actions.
If you trust the source of this workbook, click Yes to enable queries to external data in this workbook. If you are not sure, click No so that changes are not applied to your workbook.
Do you want to enable queries to external data in this workbook?
The reason behind this is Excel Services is configured to warn on data refresh.
Open SharePoint 2010 central administration, then go to Application Management.
Then click on Manage service applications.
Then from the list of service applications, select Excel Service.
Then Click on Trusted File Location in Excel services application page.
Next Select http:// link Excel Services Application Trusted File Location.
In Excel Services Application Edit Trusted File Location page, clear "Warn on data refresh" checkbox in External Data section and click on Ok.
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