It happens quite so often that we need to use mathematical symbols and other alphanumeric characters in the presentations, and PowerPoint shows such characters as spelling mistakes and mark them with a red squiggly line. However, you can bring Spell Check dialog anytime to ignore the errors or add the frequently used characters to its word dictionary. Since it’s quite a tiring process to manually select each error and take it off the list of spelling mistakes, you can choose to permanently hide the spelling mistakes from the presentation. In addition, you can also turn off check spelling as you type option to completely disable the spell check feature. Turning spell check is not recommended, but it may come helpful in situations where you are creating a presentation that contains a lot of acronyms, special characters, mathematical expressions, code etc. Once turned off, PowerPoint stops checking the presentation slide content for spelling and grammar mistakes.
In order to disable the spell check feature, open the presentation, click on the File menu, and select Options.
It will bring up PowerPoint Option. Now, select the Proofing section from the left sidebar. Now, scroll down the main window to find When correcting spelling in PowerPoint section, and enable Hide spelling errors option. This will immediately hide all the spelling mistakes. As stated earlier, you can also choose to disable check spelling errors option and enable option to use contextual spelling errors.
Once you’ve tweaked with spell check option, save the presentation, close it and open it again for the changes to take effect.