Master slides

Hello Rebecca

Thank you for your question and welcome to the forum.

As far as I'm aware, it's not possible to do this in PowerPoint (although obviously it would be very useful). If the designs you are referring to (e.g. logo) are part of an image which is inserted into the background of a master slide, then it would stop people from being able to say, for example, resize the logo image.

The other suggestion is to make sure that your master slides are saved in a template file, which you can then password protect to open or modify if you like. I realise this doesn't stop people from making changes to the master slides once they have created a new presentation from the template, but it would stop people from messing about with the actual template itself.

Kind regards
Amanda