Using the tools
A PDF asks for a password — can I open it?
What unlock can do when you know the password, and why a file you cannot open stays locked.
Updated
Unlock removes the password from a copy
If you know the password, Unlock PDF produces a copy that opens without asking for it again. This is useful for a bank statement you need to merge or compress, where the password gets in the way of the next tool.
The original stays protected. Only the new copy is unlocked.
If you do not know the password
There is no legitimate way around it. A password-protected PDF is encrypted with that password; guessing it is a brute-force attack, and we do not offer one.
Ask the sender for an unprotected copy or the password — that is faster than any tool.
Protecting a file you are sending
Protect PDF adds a password to a copy so it can travel over email. Send the password through a different channel than the file, or the protection adds nothing.
Tools mentioned
Still stuck?
Tell us the tool, the file size and the exact error text. That is usually enough to reproduce it.