Powerpoint presentation won't recharge


I included a Powerpoint presentation in a layer. On the side, I modify the presentation and save it. Manycam won’t update the presentation, which is okay.
But when I reload the presentation, by re-selecting the file, it won’t update it either. I have to charge another Powerpoint file, then re-charge the intended presentation.
Could you update the presentation at each load of the Powerpoint file, even if it’s the same one, please?