There is one legitimate, non-malicious way to recover a lost instructor password if you have access to a saved student submission.
Here’s the ironic twist: When a student completes an activity and saves their work, the .pka file contains the student’s configuration, but not the instructor’s password. You cannot retrieve the password from a student’s save file. Cisco Packet Tracer Activity Wizard Password Crack
However, if you have a backup of the original instructor’s file (the one before it was distributed), some older versions of Packet Tracer allowed you to use a debug command: There is one legitimate, non-malicious way to recover
Cisco deliberately removed these backdoors after v6.3. Cisco deliberately removed these backdoors after v6
Some third-party tools claim to be able to crack Packet Tracer activity passwords. However, using such tools is not recommended, as they may:
Legitimate solution: Ask the instructor to recreate the activity or contact Cisco support. Many institutions have backups. If you are the instructor, use Packet Tracer’s Network Control Panel (under Extensions -> Activity Wizard) to create a new activity from scratch. There is no legitimate password recovery tool provided by Cisco.