Application_Startup() not firing

I've code in the "ThisOutlookSession" module.

Application_ItemSend works, events are triggered when sending mail.

Application_Startup runs when I initiate it manually after Outlook has been opened - not upon startup.

Making the sub private makes no difference - neither does making the variables public.

I have macro settings on "Enable all macros" in the Trust Center.

I'm on Outlook 2016 on a PC running Windows 10 Enterprise.

I have researched the issue intensively.

Option Explicit

Dim add_str As String

Public Sub Application_Startup()

    Dim olNs As Outlook.NameSpace
    Dim Folder As Outlook.MAPIFolder
    Dim SubFolder As Outlook.MAPIFolder
    Dim Item As Object

    Set olNs = Application.GetNamespace("MAPI")
    Set Folder = olNs.Folders("albrobin@workmail.com").Folders("WORKFLOW").Folders("Reporting")

    For Each SubFolder In Folder.Folders
        If SubFolder.items.Restrict("[UnRead] = True").Count > 0 Then
            For Each Item In SubFolder.items
                Item.UnRead = False
            Next
        End If
    Next

End Sub


Public Sub Application_ItemSend(ByVal Item As Object, Cancel As Boolean)

    If TypeName(Item) <> "MailItem" Then
        Exit Sub
    End If

    If Item.Subject Like "RE: *" _
        Or Item.Subject Like "AW: *" _
        Or Item.Subject Like "FW: *" Then
        Exit Sub
    End If

    UserForm1.Show

    If add_str = "[URGENT] " Then
        Item.Importance = olImportanceHigh
    End If

    Item.Subject = add_str & Item.Subject

    add_str = vbNullString

End Sub


Public Sub routine(str_ As String)
    add_str = Replace(str_, vbCrLf, " ")
    add_str = "[" & add_str & "] "
End Sub


Sub show_form1()
    UserForm1.Show
End Sub

I tested your code and I’ve ran into the same problem. I have solved this problem by restarting my PC and adding the Public Sub Application_Quit() method.