Kon-Boot

Kon-Boot (aka "konboot", "kon boot") is a software utility that allows users to bypass Microsoft Windows passwords and Apple macOS passwords (Linux support has been deprecated) without lasting or persistent changes to system on which it is executed. It is also the first reported tool capable of bypassing Windows 10 online (live) passwords and supporting both Windows and macOS systems. It is also a widely used tool in computer security, especially in penetration testing. Since version 3.5 Kon-Boot is also able to bypass SecureBoot feature.
History.
Kon-Boot was originally designed as a proof of concept, freeware security tool, mostly for people who tend to forget their passwords. The main idea was to allow users to login to the target computer without knowing the correct password and without making any persistent changes to system on which it is executed.
First Kon-Boot release was announced in 2008 on DailyDave mailing list. Version 1.0 (freeware) allowed users to login into Linux based operating systems and to bypass the authentication process (allowing access to the system without knowing the password).
In 2009 author of this software announced Kon-Boot for Linux and 32-bit Microsoft Windows systems. This release provided additional support for bypassing Windows systems passwords on any Windows operating system starting from Windows Server 2008 to Windows 7. This version is still available as freeware
Newest Kon-Boot releases are available only as commercial products and are still maintained. 
Current version is able to bypass passwords on the following operating systems:
Technology.
Kon-Boot works like a bootkit (thus it also often creates false positive alerts in antivirus software). It injects (hides) itself into BIOS memory. Kon-Boot modifies the kernel code on the fly (runtime), temporarily changing the code responsible for verification user's authorization data while the operating system loads. 
In contrast to password reset tools like CHNTPW (The Offline NT Password Editor), Kon-Boot does not modify system files and SAM hive, all changes are temporary and they disappear after system reboots.
Limitations (prevention).
Users concerned about tools like Kon-Boot should use disk encryption (FileVault, Bitlocker, Veracrypt etc.) software as Kon-Boot is not able to bypass disk encryption. BIOS password and enabled SecureBoot feature is also a good prevention measure. However Kon-Boot version 3.5 is able to bypass SecureBoot feature.