Can this open a file whose password I do not have?

No. It removes a password you know — it does not break one you do not. There is no back door here, and a tool that claimed otherwise would be lying to you.

Why do I need this at all?

Mostly to stop retyping a password every time you open a document you already have rights to, or to make a file printable and searchable again.

Can it open a PDF if I do not know the password?

No. It removes a password you can supply, so you stop typing it every time. Breaking into a document you cannot open is not something this site does.

What about a PDF that opens but will not let me print?

That is a permissions password rather than an open password. Supply it the same way and the restriction comes off.

Unlock PDF

Remove a password you already know, so the file opens without prompting.

Processed on our server, then deletednew

This removes a password you know — it does not break one you do not. The file is unlocked on our server and deleted straight after.

Report a problem

How to use Unlock PDF

Choose the password-protected PDF.
Enter the password you already know.
Press Unlock and download a copy that opens without prompting.

Questions

Can this open a file whose password I do not have?: No. It removes a password you know — it does not break one you do not. There is no back door here, and a tool that claimed otherwise would be lying to you.
Why do I need this at all?: Mostly to stop retyping a password every time you open a document you already have rights to, or to make a file printable and searchable again.
Can it open a PDF if I do not know the password?: No. It removes a password you can supply, so you stop typing it every time. Breaking into a document you cannot open is not something this site does.
What about a PDF that opens but will not let me print?: That is a permissions password rather than an open password. Supply it the same way and the restriction comes off.

Auf Deutsch: PDF-Passwort entfernen