You built the deck on your laptop, it’s perfect, and then you plug into the projector on someone else’s machine and every heading has jumped to two lines. The talk starts in four minutes. Here’s what happened and how to avoid it next time.
Why a deck breaks on another machine
Fonts substitute first, and most often: a .pptx names its fonts rather than containing them, and if the host machine doesn’t have the one you used — most brand fonts, and even some Microsoft ones that ship only with newer Office versions — PowerPoint swaps in something else. The replacement has different letter widths, so a title that fitted on one line now wraps, pushes down, and overflows its box. Versions render differently too: PowerPoint 2016, Microsoft 365, PowerPoint for Mac, Keynote, and Google Slides each handle text autofit, shadows, gradients, and SmartArt with small differences that show up as shifted elements. Linked media goes missing if video or audio was inserted as a link rather than embedded, since it lives on your drive and becomes a grey box on another machine. And screen shape differs — a 16:9 deck on a 4:3 projector gets letterboxed or cropped depending on settings, which can cut off content near the edges.
The reliable answer is bringing a PDF too. Convert the presentation to PDF and carry both files — a PDF embeds its fonts and fixes the position of everything on the page, so slide 12 looks the same on every machine, projector, and phone, and it opens without PowerPoint installed, which also covers the case where the host laptop has no Office licence at all. You lose animations and transitions in the PDF, so present from the .pptx when it works, but when it doesn’t, having the PDF on a USB stick and in your email turns a crisis into a shrug.
What to do the day before
The day before, a few things are worth checking: embed or avoid unusual fonts (in PowerPoint, File → Options → Save → Embed fonts in the file, or design in fonts that exist everywhere); embed video and audio rather than linking it; turn off text autofit on titles so you find out at home that a line is too long, rather than watching it shrink to 12pt on stage; set the slide size to match the room’s projector if you know it; and export a PDF and flick through it, since anything that’s going to break shows up here.
If you’re emailing slides for people to read rather than presenting them, send the PDF and only the PDF — it’s smaller, it can’t be edited, it opens on a phone, and nobody sees your speaker notes. Both the older .ppt format and modern .pptx convert, up to 25 MB per file. If the deck’s too big to email, compress the PDF, since image-heavy presentations shrink a lot. If it’s confidential, lock it with a password. Handing out one section? Split the PDF into the part they need. Need the slides as pictures for a website or a social post? PDF to Image gives you each slide as a JPG or PNG. And if someone sends you a PDF deck you need to edit, PDF to PowerPoint converts it back into editable slides.
Two related guides: How to Convert PowerPoint to PDF for the step-by-step, and How to Compress a PowerPoint Presentation if the deck is also too large to send.
Lock in the layout with the free PowerPoint to PDF converter — no email, no account, and it’s not kept anywhere.