VBA Powerpoint how to Macro_BeforeRun?

If your question is "how to trigger an event before a presentation is saved" then the answer is as follows. This is a multi-step process.

1. Add a Class module (not a Standard module) called CEvents and add the following code to it:

Dim WithEvents ppApp As PowerPoint.Application Sub Initialise() Set ppApp = PowerPoint.Application End Sub Private Sub ppApp_PresentationBeforeSave(ByVal Pres As Presentation, Cancel As Boolean) MsgBox "Before save for " & Pres.Name End Sub 

2. Follow the process as described in this SO answer: https://stackoverflow.com/a/38295674/11318818

3. In the same Standard module that you put the MyOnloadProcedure() procedure, add a module-level declaration: Dim mEvents As CEvents

4. In the MyOnloadProcedure() procedure, replace MsgBox "Hello" with:

Set mEvents = New CEvents mEvents.Initialise 

5. Save your presentation (it must be macro-enabled eg .pptm). Close and re-open your presentation. Click save to test and you will see the message box.

Note that as soon as you make any module-level edits to your VBA code, the PresentationBeforeSave event will stop triggering until you close and re-open the Presentation ... this is because the module-level variables loose state when you make such edits, state is then re-set when the presentation is re-opened.