Reminder to check before you present
My takeaway lesson from this experience: Double check all special symbols that you are using in your presentation on the setup that you will be using. Sometimes this means checking in the room right before your presentation, so make sure you arrive early and you know which slides you have to change if the setup has a different font configuration. I had not realized that changing the operating system could change the font definitions, but now you can learn from the lesson I was taught. Another approach you could use is to save the symbol character as a graphic and use the graphic instead, since font definitions don’t affect graphics. I have done this in the past and it works quite well.
Glad that I can continue to enlighten you as I learn lessons in public!