This issue happens with older templates. When I open older files, it gives this message: The Operation cannot complete because of an unknown error. [x!fd]. I have a gotten this message in 2017 and Adobe step up to fix the issue, but the previous update and this one still has the issue. I can open these in previous versions of Illustrator. It's really a pain to fix the file as I have to save in Illustrator 8 and then reimport the text as this conversion converts the type to curves. Now to make matters worse if I save the file back to version 8 the new Illustrator wont open it. so I now need a previous version of Illustrator just to save back to Illustrator 8. I attached a simple file for you to look at that gives this issue.