Layers flatten when opening PDF files in Illustrator

[Newby08]

Hi!  My co-workers and I are having a similar problem as other discussions but I haven't seen a solution or reason why yet?

There are three of us all working with Illustrator Adobe CC 2015 32 bit (yes - 2015 due to Company decision) one of us is on a Mac and 2 of us are on PC

We work on Illustrator files with many layers, and we save them as PDFs (with Preserve Illustrator Editing capabilities and Create Acrobat Layers from Top-Level Layers checked).  Instead of working from the native files, we open the PDFs and make the edits and then save as PDF again with same settings as above.  (Although the same thing happens when we try to open the ai file)  Sometimes one of us will try to open a PDF in Illustrator and get this message: "This file was generated by a newer version of Illustrator. Would you like to import this file? Some data loss will occur" and the file will open with only one flattened layer.

We are trying to determine if it is a bit thing (32 bit vs 64 bit), PC vs Mac thing, or CC version issue - that is the question?  What is causing this non-compatablity that flattens the layers?

Thank you.

[Monika Gause]

Are saving and opening directly from a server?

Can you check if that also happens when you first copy the file to your harddisk then open, work locally and only after saving transfer the file back?

Illustrator files get damaged in some environments.

Also: Mac OS and a Windows Server or vice versa don't behave well when you directly work on the server.

Please do also watch this about saving Illustrator files:

Mysterious things Illustrator does - Saving files on Vimeo

[Myra Ferguson]

I'm on a PC, but I'm running Illustrator CC 2017.0.2 64-bit. I couldn't reproduce saving a PDF that flattens the layers with Preserve Illustrator Editing Capabilities and Create Acrobat Layers from Top-Level Layers selected. I did however notice some settings that affect whether Preserve Illustrator Editing Capabilities and Create Acrobat Layers from Top-Level Layers are available. What are your settings for Standard and Compatibility in the Save Adobe PDF dialog? Maybe try setting Standard to None and Compatibility to Acrobat 6 or above.

[Newby08]

Thank you.  I think I understand better how AI and PDF files work.  While you can select an earlier version when saving an AI file, you do not have that choice when saving a PDF file; the ai embedded in the PDF will be the current version it was saved in.  So anyone who tries to open the PDF in a version of Illustrator older than the version that that PDF was saved in, will get that message and layers will be flattened.  Is this right?

So a follow up question is:  Will this happen with diff versions of CC when saving PDFs?  Or are CC versions of Illustrator backward compatible?  ie, can someone who has CC 2015 open a PDF that was saved by someone who has CC2017 and still have layers, editable text?

[Monika Gause]

Newby08  schrieb

So a follow up question is:  Will this happen with diff versions of CC when saving PDFs?  Or are CC versions of Illustrator backward compatible?  ie, can someone who has CC 2015 open a PDF that was saved by someone who has CC2017 and still have layers, editable text?

Please watch the video I posted above.

Then:

Any version Illustrator CS and higher works this way.

A PDF (with AI editability) saved from version X cannot be opened in earlier versions.

As for files from Illustrator CC 2017: I can only test CC 2014 and it won't open the embedded AI, only the PDF. So layers are flattened.