Why when I import a PDF to Corel Draw X6 I get "font substitution for missing fonts", the I allow the temporary or permanent font substitution and then "The file is corrupted"? Even when I use a font that is available?
Also Illustrator could have problem with this file, according with the version (newest versions open it better)Sometimes, it's enough a Mask for having the "corrupt" message when you tried to open with CorelDRAW. WHEN THIS IS THE REASON, releasing the mask is enough to allows to open the file correctly. But not always is the same reason. And it's not for this file, of course. With this file, what I did was "print to PDF" using the Acrobat PDF printer. That creates a new PDF with the settings we choose
I can explain it but it won't solve your problem. Adobe sells licenses to use PDF to those who write applications, it's one of their single largest revenue streams. However just as they did with EPS years ago they are lax with controlling it. In fact with Illustrator they abuse the definition, that's ok they own it they can do what they want.
Applications go about creating effects their way, Adobe does them their way, Corel their way ECT. CAD programs run amok having CAD means next to nothing in terms of cross application compatibility.
I suspect that if you get a PDF created in an application that agrees with how your application of choice imports and handles images and transparency then if opens if not then no. I suspect Corel and Adobe are trying to layer and render the transparency for editing their way and it's a no show.
Files from CAD or going to CAD are a challenge, we use 11 vendors that require CAD, they use 8 or 9 different proprietary CAD programs. So we have found ways to make perfect PDF files for them.