If you aren't already on the sheet, it won't work.
Try this:
Code:Sheets("Master_Week").Activate Range("J3").AutoFill Destination:=Range("J3:BH2560"), Type:=xlFillDefault
Sheets("Master_Week").Activate
Range("J3").AutoFill Destination:=Range(newCol), Type:=xlFillDefault
What aboutCode:With Sheets("Master_Week") .Range("J3:BH3").AutoFill Destination:=.Range("J3:BH2560"), Type:=xlFillDefault End With
It worked...Sounds like MS have changed something, as it doesn't work in 2013 either.