After certain edits in PowerPivot in Excel 2013, Power Query connections are read-only and further edits are blocked in Power Query.
After you applyOctober 13, 2015, update for Office 2013 (KB3039800), September 8, 2015, update for Office 2013 (KB3039739) and MS15-099: Description of the security update for Excel 2013: September 8, 2015 (KB3085502), the edits are blocked and Power Query can change the queries in these connections. The following actions in PowerPivot are blocked for tables that are loaded by using Power Query:
Change the data type of a column
When you try to do these actions, you will receive the following error message:
This table was created with Power Query. To change this table, use Power Query instead.