Created copied Excel Worksheet throws 424 error - excel

Question

The goal is to create a copied sheet that is renamed in the current month and year. The copied sheet is being created in the workbook, however a default name is given to the sheet. What am I missing?
Private Sub Button3_Click()
Dim wb As Workbook
Dim ws As Worksheet
Dim nowMonth As Integer, nowYear As Integer
Application.ScreenUpdating = False
Application.Calculation = xlCalculationManual
nowMonth = Month(Now)
nowYear = Year(Now)
Set wb = ActiveWorkbook
On Error Resume Next
Set ws = wb.Sheet(nowMonth & ", " & nowYear)
On Error GoTo 0
If Not ws Is Nothing Then
MsgBox "The Sheet called " & nowMonth & ", " & nowYear & " already exists in the workbook.", vbExclamation, "Sheet Already Exists!"
Exit Sub
Else
Set ws = ActiveSheet.Copy(after:=wb.Sheets(wb.Sheets.Count))
ws.Name = nowMonth & ", " & nowYear
End If
Application.ScreenUpdating = True
Application.Calculation = xlCalculationAutomatic
End Sub

Answer 1

The problem is in Set ws = ActiveSheet.Copy(after:=wb.Sheets(wb.Sheets.Count)), because it is trying to Copy and Set in the same time and this is a bit too much.
Change the code in the condition to this:
If Not ws Is Nothing Then
MsgBox "something"
Exit Sub
Else:
Set ws = ActiveSheet
ws.Copy after:=wb.Sheets(wb.Sheets.Count)
wb.Worksheets(wb.Sheets.Count).Name = nowMonth & ", " & nowYear
End If
In general, avoid using Active and Select in VBA - How to avoid using Select in Excel VBA.

Answer 2

Worksheet.Copy disappointingly doesn't return a reference to the created sheet. Instead, it has the side-effect of adding a new sheet to the workbook, and activating it.
So after running Worksheet.Copy, the ActiveSheet is the newly created sheet.
ActiveSheet.Copy after:=wb.Sheets(wb.Sheets.Count)
ActiveSheet.Name = nowMonth & ", " & nowYear
Now, this code is confusing/misleading, because it looks like the two statements are qualified with the same object, but they aren't.
What's not clear, is why and how the ActiveSheet is guaranteed to be the correct sheet to copy; we're working off the ActiveWorkbook and we don't really care which sheet is active.
I'd suggest to make the copy work off an explicit sheet:
Dim sourceSheet As Worksheet
Set sourceSheet = wb.Sheets(wb.Sheets.Count)
sourceSheet.Copy after:=sourceSheet '<~ new sheet becomes ActiveSheet
ActiveSheet.Name = nowMonth & ", " & nowYear
And now everything is as clear as it gets.