Ars Technica

VBA: Connection string results in "External table is not in the expected format"

I'm attempting to connect to an excel file using an ADO recordset. There is a column in this that I need the sum of for a report. I'm familiar with ADO connections ...
How-To Geek on MSN

Why you should never link to another Excel workbook (and what to do instead)

Stop using fragile direct links—Power Query creates faster, automated, and more robust workbook connections.