I password-protected a PDF with Acrobat Pro 2020, then tried to open it again. Instead of being asked for the password, however, I received an error message that told me the file was corrupted and couldn't be repaired. What!!!
I tried opening the encrypted, and allegedly "corrupted", file in MacOS Preview, and it worked! I typed in my password, and the file opened like a charm.
As if that wasn't weird enough, here's the next level: I encrypted a PDF in Preview this time, and saved it. When I tried to open it in Acrobat, I was asked for the password, typed it in, and it worked, too!
Now let't get this straight: In Acrotbat Pro, I can open documents encrypted in Preview, but not those encrypted in Acrobat itself?
Did you try to open it in Preview first, and then tried it in Acrobat, by any chance?
What exact version of Acrobat please (like 2020.123.45678?)
Thanks for replying, also to try67. Opening the file in Preview first didn't change anything. The Acrobat version is 2020.001.30020. But I don't think this plays a role here. - Why? Because here's what I found today:
Encrypting works in general. It only fails and shows the above mentioned symptoms with OCR files.
That't what I usually do with scans - I OCR them. And no, not in Acrobat, but in ABBYY Fine Reader. Obviously, the two don't get along too well. For the sake of testing, I tried using Acrobat's OCR function and then encrypted the file. And bingo, this time it worked! I could open the file with my password, the way it's supposed to be.
So I guess there is no fault with Adobe here. I'll have to live with this little incompatibility, but now I at least I know how to handle this.
So thanks again for trying to help me here. Maybe someone will run into the same problem - here's the solution!
I didn't ask in order to encourage you to try it, but to warn you that opening it in Preview may very well cause this issue, as it's a buggy application that corrupts PDF files just by opening them...
Actually that does sound like a fault in Acrobat, and a serious one. I'm glad you found a way to avoid it. I can confirm the version you are running (2020.001.30020) is the latest available update to Acrobat 2020, as of May 2021. I asked because I think I remember a similar problem being fixed.