What does "Create PDF Compatible File" mean in Illustrator?
What does the "Create PDF Compatible file" option when saving an Illustrator file do?
What happens if I uncheck it when saving my work?
In illustrator you can save PSD and AI nativily, That's mean Ai and PDF are replicas of the same artwork in the same file, you can open AI files in Acrobat nativily as well as opening PDF in Illustrator. what this option did is to let illustrator save your artwork inside AI or disable this feature.