Illustrator sometimes doesn't launch after you apply the Illustrator CC 17.0.1 update. Adobe has released an update Illustrator CC 17.0.2 to fix this issue.
Open the Creative Cloud app () from the menu bar, and allow installation of the available Illustrator update.
Apply this solution only if Solution 1 doesn't resolve the problem and Illustrator doesn't launch:
- After the 17.0.1 update was applied, and,
- The Mac-only update (17.0.2) has not been applied.