With Worksheets("Data")
LastRow = .Cells(Rows.Count, "A").End(xlUp).Row
.Range("J3:T3").AutoFill Destination:=.Range("J7:T" & LastRow)
_
, Type:=xlFillDefault
End With

I'm receiving Run-time error '1004'
AutoFill method of Range class failed

This works perfectly fine on another worksheet and different range.

TIA
Gerry