I have just bought an Adobe stock Illustrator file .ai as a trial.
This is my first purchase of Adobe stock. I do not have Illustrator. I would normally work on .ai files bought from other providers with either Affinity or iDraw on my Mac, I have never had a problem previously doing this.
For this particualr Adobe Stock image I am unable to open the file on either of those two packages "this file does not contain a valid PDF stream". I can open the file rendered on Adobe Photoshop CC. Is there something Adobe are applying to the .ai file that limits its use to Illustrator only. If this is the case this should be made plain on the site and for me means that I shall not be using Adobe Stock for vector illustrations in future.