Thank you Azaziah. The irregularities are probably the OpenLP integration with the presentation software. I understand the irregularities when, for example, creating a presentation with Powerpoint and then using Impress to display it or vice versa. My problems are things such as Preview not working or slides not showing in the Live window or preview behaving differently when used from Library and Service Manager. These seem to be often, but not always, reproducible. I get these even if I create an .odp file from scratch in Impress and then use OpenLP/Impress to display it. The problems seemed to go away very briefly recently when I installed LibreOffice instead of OpenOffice (I've tried switching between the two several times).<br><br>Essentially, I'm wondering if it's worth spending money on Powerpoint. I'm happy to do that if it will fix the problems but I'd hate to waste the money if it left me with the problems. Maybe my next thing to try is to use Powerpoint Viewer. Any advice would be very gratefully received - what combinations of Windows/OpenLP/presentation software are people using successfully?<br><br>BTW, I have OpenLP 2.4.6, not 2.4.5, but 2.4.6 isn't listed as a version when posting a new topic in these forums.