Illustrator comes up with an error when opening PDF files

[Eimear2]

Comes ip with 'Fix unknown error ..' ??  Urgent help needed! 

[Monika Gause]

PDFs are not "opened", but imported. Meaning: It can fail.

Did you save the PDF from Illustrator? With "Illustrator editing capabilities"?

[Eimear2]

Hi

It originated as a PDF. I used to be able to 'open' and choose Illustrator. That failed. I have tried saving as a .ai file but there is no option to do that on Creative Cloud's version of Adobe Acrobat.  

[Monika Gause]

Where did it originate? In Illustrator?

Illustrator does not "open" PDFs. PDF is not a native file format for Illustrator.

Illustrator is not a general purpose PDF editor.

[Eimear2]

Illustrator has opened PDFs up until I tried yesterday! I have been doing it for years but now it has stopped. Try highlighting a pdf file. Go into 'Finder' on an Apple Mac and select 'Open with' ... you get a choice of 'compatible' programmes. Ergo, it worked before but not now. I can open Illustrator and 'place' but I do not get the same capabilites of being able to separate layers and amend the base pdf as I used to. 

Adobe = Illustrator, Photoshop, Acrobat, In-Design and you can bridge as well as open up. So when you say Ilustrator is not  general purpose PDF Editor - I did it. I was able to do it. Maybe you have exhausted your advice. 

[Monika Gause]

Maybe you have exhausted your advice. 

By @Eimear2

Oh, thank you very much. So if you don't believe me, then maybe you believe Adobe's PDF gurus (and you might know that Adobe has invented the format, right?) telling you just the same: https://prepression.blogspot.com/2014/09/the-ten-commandments-of-pdf.html

Can you still import other PDFs into Illustrator?

[Eimear2]

I will look at that. Thanks