Anyone have any idea why this won't work? All I am trying to do is copy the
contents on an entire worksheet from one workbook, and paste over the
contents of a sheet called "Data" in another workbook.

Set bk = Workbooks.Open(myFileName)
bk.Worksheets(1).Cells.Copy
ThisWorkbook.Worksheets("Data").Cells.Paste
bk.Close savechanges:=False