Run-time error '91' Help

[Pookiemeister]

I'm not sure what I am doing wrong here. Sometimes when I open my worbook, I will get a Run-time error '91': Object variable or With block variable not set and sometimes I won't get it. That makes no sense but when I added the Option Explicit to the top of the code I get the error message every time.
When I step through the code, the error occurs after

ActiveWindow.Visible = False

Full Code below:

Option Explicit
Private Sub Workbook_Open()
    
    Dim result As String
    
    ActiveWindow.Visible = False


    result = MsgBox("Do you want to open the product list worksheet prior to opening the userform?", vbYesNo + vbDefaultButton2, "Select Option")
        
    If result = vbYes Then
        Windows("Happy.xlsm").Visible = True
    Else
        selectFilefrm.Show
    End If
End Sub

I'm also not sure if result should be a string and not something else.

Dim result As String

Thank You

 

[Fluff]

You don't need Result, try

Private Sub Workbook_Open()
    
    
    ActiveWindow.Visible = False


    If MsgBox("Do you want to open the product list worksheet prior to opening the userform?", vbYesNo + vbDefaultButton2, "Select Option") = vbYes Then
        Windows("Happy.xlsm").Visible = True
    Else
        selectFilefrm.Show
    End If
End Sub

 

[Pookiemeister]

I'm still getting the same error message with the above code at the same place. Now my message box doesn't even appear. Thank you for your help.

 

[Fluff]

What line is highlighted when you click debug?

 

[Pookiemeister]

ActiveWindow.Visible = False

 

[Fluff]

Does it take long for that workbook to open?

 

[Pookiemeister]

No

 

[Fluff]

In that case I'm not sure why you are getting the error.

 

[Pookiemeister]

So what happened to MsgBox?

 

[Fluff]

If you get an error on this line

ActiveWindow.Visible = False

The code never gets to the message box