Can't open PDF file on mac

Report · Nov 18, 2020

Hi there.
It's an annoying problem. I have some PDFs that I underlined (and added some posts) when reading to highlight key passage in my work and saved them in an appropriate new folder. Today it seems that Acrobat Reader DC can't open them. Their format name has changed from "Adobe PDF document" to simply "PDF". Interestingly, when it comes to see the info of these files seems that it's impossible to open them with Acrobat Reader (already updated to the newest version). Even with Mac preview it is not pobbile to see the pages as other 'regular' pdfs. Is there any method to have them back, possibily with the underlined parts (along with the posts)?

Thanks in advance.