I have a better alternative for you if you wish to open encrypted 7zip files, and that is the eSoftTools 7zip password recovery tool. There are many features in this software, which is the greatest. Any password combination that it has technical support for can be unlocked. All users can contact support via email or live chat. The first three characters and password for 7zip files can be unlocked using the demo version. It employs the Mask Attack, Brute Force Attack, and Dictionary Attack techniques to break the password of 7zip files. 

Know More: Open encrypted 7zip files