This error can appear if you try to open a password-protected Word document and you do not provide the correct password.
Passwords prevent unauthorized access to documents. A password-protected document can only be opened if the correct password is supplied. If you forget or lose the password, you cannot open the document.
NOTE: Passwords are case sensitive. Before entering a password, verify that the CAPS LOCK keyboard option is not turned on. If you are using a multi-lingual enabled computer, make sure that the language that was used to create the password is enabled when you enter the password.