Try running this code in Excel, you should find the first loop works fine, and the cells are named. The second loop fails, why? I have searched the internet but can't find anything on it.
Sub name_those_cells()
Dim i As Long
Dim objRange As Range
Cells(1, 2).Value = "started"
For i = 1 To 56
Range("a" & i).Select
ActiveWorkbook.Names.Add Name:="a_" & i, RefersToR1C1:="=Sheet1!R" & i & "C1"
Next i
Stop
For i = 65480 To 65536
Range("a" & i).Select
ActiveWorkbook.Names.Add Name:="a_" & i, RefersToR1C1:="=Sheet1!R" & i & "C1"
Next i
Cells(1, 2).Value = "finished"
End Sub
Sub name_those_cells()
Dim i As Long
Dim objRange As Range
Cells(1, 2).Value = "started"
For i = 1 To 56
Range("a" & i).Select
ActiveWorkbook.Names.Add Name:="a_" & i, RefersToR1C1:="=Sheet1!R" & i & "C1"
Next i
Stop
For i = 65480 To 65536
Range("a" & i).Select
ActiveWorkbook.Names.Add Name:="a_" & i, RefersToR1C1:="=Sheet1!R" & i & "C1"
Next i
Cells(1, 2).Value = "finished"
End Sub