Hi @Chris Po ,
Welcome to Q&A forum!
Which version of Office are you using? Please go to File>Account in PowerPoint to check the detaild version and share it with us.
According to my research, if the system cannot read the fonts you use in your presentation, this error message will be thrown.
Generally, we have the following 2 solutions:
- Switch to basic font.
As you have done so far, the format layout may overlap or change, which may require you to adjust it manually.
- Download and install the new font.
Please refer to: Download and install custom fonts to use with Office.
If you want to share it with other users, you should attach the downloaded font and leave a note.
In addition, I think you may also need to learn about: Embed fonts in documents or presentations.
Hope the information could help you. Any updates, please let me know.
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