I can't recall this happening before, and if it did, it's extremely rare. I've always been able to open/view PDF attachments w/o Adobe Reader. So why all of the sudden am I seeing a "Get Adobe Reader Now!" image to view attachments? Are they somehow protected and require Adobe Reader?
IMAC (RETINA 5K, 27-INCH, LATE 2015), macOS High Sierra (10.13.3), Preview
What you see is an advertisement. You do NOT need to get Adobe software to read pdf files on your mac.
You can use the built in Preview app to open PDF's.
No need for any Adobe product.
To reiterate, the PDF attachments will NOT open with Preview or Quick Look. I was not aware that some PDF's could not be viewed as such and would require Adobe Reader/Acrobat.
Yes there are PDFs that are created using Adobe software that have forms, javascript, or sometimes accessibility built-in that require Adobe software to render. Look at the example below which is a public government PDF form.
I know this as I have created PDF documents. I was once an Adobe form developer for a third-party.
Not always some PDFs depending on how the PDF was create it may only work with Adobe software.
This is common with PDFs that have fillable forms or javascript code.
Why does PDF attachment in iOS/macOS Mail require Adobe Reader?
