IMPRESS double vieuw

Opening a ppt/pps in impress gives every slide twice at once = mostly covering one another.
Sometimes text is mixed too = letters all over the page ex. around a picture, making the text unreadable.
Opening a pps always opens a slideshow but we cannot open it in impress to make changes or scroll down through the slides.

Please Kate, what is your Operating System and LibreOffice version?

This is absolutely normal, When LibO or his brother AOO open a MSO document like ppt/pps they try to read and make an interpretation of some proprietary code from MSO/Power-Point all these *pps or *ppt contain some codes exclusive to Microsoft. Depend how you have formatted your documents, if the layers/underlayers, styles, effect FX are complicated, you will have many chance to see a different formatting between these different software.

The better way is to built your presentation with LibreOffice witch is a standard document, if you make your presentation with PowerPoint, and use the special effect or the formating of power point you will be able to have a big mess with other software…

More your document have a simple formatting, more the compatibility will be better

To open a pps-ppt document with LibreOffice (or any other compatible software ) use the right click of your mouse on the document you want to open and on the contextual menu choose “open with …” the software you want to use, until you assign LO as default for pps or ppt