Setting Macro Security - Excel 2016

At the top Click on “File”
Then click on “Options”

Look for and then click on “Trust Center”
A box that says Microsoft Trust Center will pop up.
In the lower right hand corner of that box you will need to click on “Trust Center Settings”
You will then select “Trusted Locations”

Near the bottom you will see “Add new location”…click on that.

This box will pop up…

Type the path name of where the spreadsheets are, for instance, c:\as400da

Also check the box "subfolders of this location are also trusted"
Then you’ll click “OK” and then click “OK” again.

Close and reopen the spreadsheet.

The error with the security warning will be gone.