my old copy of Acrobat suddenly cant open pdfs

[Nesta Hall]

Hi, suddenly in the last week ive been unable to open PDFs sent to me by multiple different businesses.  The error message says the pdf is encrypted.  Ive never seen that error message before.  Any ideas?  I wondered if my version of Acrobat was out of date, im using Adobe Acrobat 8 Pro, which i think is dated 2008 (!), and dates back to the small biz i used to run.  Could it be?  Anyway, it now appears the acrobat is only available as a subscription service - DC or Pro?  Thanks in advance.

[ls_rbls]

Well, normally if it says the file is encrypted is because the author of the document(or the last person who viewed the document), set  a password to enforce copying, printing, or editing restrictions. 

You may need to contact the author of this PDF document and see if they're willing to lower the  compatibility encryption level to 128 bit AES and just for your current Acrobat version so that you're able to view it and work with it in Acrobat Pro 8.

[Nesta Hall]

thanks for that.  The first pdf i couldnt open was from an engineer and as it was a stamped schematic, he did tell me that it was password protected, but only against editing.  Others have been able to open that file.  Then a week later the second pdf came in that i couldnt open, from another firm, and i realized the problem must be with me, rather then with the first pdf....   But your reply suggests that my Acrobat 8 Pro is indeed old enough that it may be unable to access files created in current versions of Acrobat? 

Meanwhile, I looked at the Adobe website: it appears that Adobe now only makes Acrobat as a Software-as-Service?  A subscription?  So that would be my only option for upgrading my Acrobat?

[Bernd Alheit]

You can buy Acrobat 2020.

When you want only view the files you can use Acrobat Reader DC.

[ls_rbls]

My reply wasn't suggesting anything about your version. It is old and unsupported...period. But that was not what my answer was.

What I was trying to explain is that when a person protects a PDF  document with password in Acrobat Pro DC, the file's encryption compatibilitty level will default to 256 bit AES. That encryption type is for versions of Acrobat X or later (not earlier). 

I am giving you the correct answer to your issue. It doesn't matter what version you have or not.

If you don't want to buy software at this time, and you want to continue to use Acrobat 8, all you have to do is tell that engineer to save the document with password but to lower the encryption Compatibility Level (just for you) so that your version can decrypt the PDF appropriately as you open it.

See slide below:

[Test Screen Name]

There IS a new kind of encryption introduced 10 years ago, long after your version. So that might be the issue. Could you please tell us the full text of the message?