Code breaks after executing copy statement in VBA

Question

If there isn't already a worksheet with the name Mcat Prepare, I want to copy worksheet MCAT and rename it Mcat Prepare. The code jerks out and terminates without giving me any errors after this line, which is my issue.

Worksheets("MCAT").Copy After:=Worksheets("MCAT") 'duplicate the worksheet after the original

The line is being executed which produces MCAT(2), but code stops after. This is the entire code:

Dim wb_MCAT As Workbook
Dim ws_MCAT As Worksheet

'Open the excel specified
    filepath = Application.GetOpenFilename("Mcat Master (*.xls), *.xls", , "Select a file", , False)

        If filepath = False Then
            MsgBox "No file selected."
        End If
    
    Set wb_MCAT = Workbooks.Open(filepath) 'set the workbook where the worksheet is located
    Set ws_MCAT = wb_MCAT.Worksheets("MCAT") 'set the worksheet to duplicate
   
'Check if a worksheet with the name Mcat_Prepare already exists
    ws_MCAT.Activate
    Dim ws_McatPrepareExists As Boolean
    ws_McatPrepareExists = False
    For Each existingMcatPrepare In wb_MCAT.Worksheets
        If existingMcatPrepare.Name = "Mcat_Prepare" Then
            ws_McatPrepareExists = True
            Exit For
        End If
    Next existingMcatPrepare
    
'If not, duplicate MCAT and rename it as Mcat_Prepare

    If Not ws_McatPrepareExists Then
        Worksheets("MCAT").Copy After:=Worksheets("MCAT") 'duplicate the worksheet after the original
        ActiveSheet.Name = "Mcat_Prepare" 'rename the new worksheet
    End If

Answer 1

Qualify the sheets with a workbook reference or use ws_MCAT.

    Dim i As Long
    If Not ws_McatPrepareExists Then
        With ws_MCAT
            i = .Index
            .Copy After:=.Parent.Sheets(i)   'duplicate the worksheet after the original
            .Parent.Sheets(i + 1).Name = "Mcat_Prepare" 'rename the new worksheet
        End With
    End If