place the code properly in the Workbook_Open event then. You must have typed it into the wrong module

In the VB Editor select WorkBook from the left drop down.

In the right drop down find WorkBool_Open

Paste your code there

Also, specify which sheet the combo is on

Option Explicit

Private Sub Workbook_Open()
    With Sheet1.ComboActions
        .Clear
        .AddItem "<Select Action>"
        .AddItem "Sort by Status, Resolve Date, Score"
        .AddItem "Extract Priority Risks"
        .AddItem "View Business Risks"
        .AddItem "View Technical Risks"
        .AddItem "View All Risks"
      'Optional: make sure all text is visible
        .Width = 142
    End With
End Sub