I can't paste the password for the protected PDF document

Instead of disabling Protected Mode altogether, disabling "Run in AppContainer" will also work (just tested it). 

Edit | Preferences | Security (Enhanced) | Sandbox protections > Uncheck "Run in AppContainer".

This was discovered by someone here:

I can't paste in the password input field – Share your feedback on Acrobat DC (uservoice.com)

I was able to fix this issue.  Try this...  From the Adobe Menu select Edit --> Preferances..  When the Preferances window pops up select Security (Enhanced) on the left and remove the check from Enable Protected Mode at startup and Enable Enhanced Security.  

Obviously this may disable some security protections but we can now paste passwords directly from emails.

Hi A_Rahman,

Please try updating the application to the latest version 19.021.20048. After updating, reboot the machine. 

- https://helpx.adobe.com/acrobat/release-note/release-notes-acrobat-reader.html

Also, check if the issue occurs with particular document or with all the secureed documents.

Regards,

Meenakshi

So I am reading this post again amd because I cannot see what type of emails are sent to the user I really can't tell what is going on. 

But taking PhilG1, BhavAce and A_Rahman1 answers as a starting point again, instead of involving the notepad process you can also try righ-clicking on the HTML email message and Select View Source, then copy the text password from the Inspect window that will open.

I am more inclined to believe this issue is also strictly related to how the PDF document where you are trying to apply the paste action of the password in text format has to do with how the document is opened by default.

Go to preferences, Documents, and where it says PDF/A View Mode select "Never" from the pulldown menu. Click OK and restart Acrobat try again.

If that does not work , here is an interesting approach: https://blogs.adobe.com/acrolaw/2011/05/how-to-remove-pdfa-information-from-a-file/ which suggests how to disable PDF/A restrictions and in the last suggestion of that thread someone suggests printing the file as PDF.

Worst case scenario, if none of the suggestions here work, then maybe a thrid-party add-on will be my last guess , where security restrictions are removed or partially removed in the document(s) that you need to copy and paste into. The fact that some users are reporting that they can paste the emailed password into a word processing application or be able to place it in the clipboard indicates that up to that point the problem does not relates to a fault with the email or HTML page.

This looks more at the security or restrictions that were applied into the document that is sent by the creator of the file.

We are getting this issue too, but only recently, on machines running Win10 v1903, Acrobat DC 19.012.20040.17853.

As suggested by PhilG1, it is to do with the formatting of text. It needs to be pasted in as plain text, so pasting into Notepad or any plain text area first (search bar, etc), and then copying and pasting that text will resolve your issue.

First copy the password into notepad or similar plain text field (like run command)
then Copy from there and paste into input box of Adobe reader. This works!!

Hello nadine,

I also forgot to add one more observation.

You mentioned that you used to be able to copy the password from the email body of the email that was sent to you.

You may want to also check if the security settings have changed at the computer level (lole group policies, permissions, or firewall and such).

Not sure if you are accessing your emails from a mail server(if one is used and if it applies to your case).

In my case at work, for example, the mail server is configured to restrict some  the users from right clicking on hyperlinks.

If a message is even missing a subject line is considered a possible spam message and it warns the user to proceed with caution when copying amd pasting from a received email.

I hope this gives you additional insights

Does this happens also when you try to type the password in that box instead of the copy and paste method?

Looks like, either the last person who edited the document disabled the capability to do what you are trying to do, OR an update changed or "enahanced" the restrictions that otherwise would've allowed access to editing using copy and paste method (depending on the point of views), OR, see if by cleaning the cached content in your "Clipboard" and other temporary folders helps in any way.

Hi Nadined,

We have tried to replicate the issue on our end. However, we can easily copy and paste the password without any issue.

Did you check if the issue occurs with some particular PDFs or with all the password protected PDF?

Try once to repair the installation. In the application, Go to Help > Repair Installation (Only for Windows).

Check if that makes any difference.

If the issue persists, please share the application and OS version on the machine. Identify the product and its version for Acrobat and Reader DC

It would be helpful if you can share any sample document on which the issue occurs.

Let us know if you need any help.

Regards,

Meenakshi