Do not install every toolbox. Many "fixed" cracks fail on specific toolboxes like "MATLAB Compiler Runtime" or "Polyspace." Install only:

for a specific MATLAB toolbox from 2012, or are you looking for installation support How do I download an earlier release of MATLAB? - MathWorks

A: Only if you hold a valid commercial perpetual license. Otherwise, it is software piracy. MathWorks audits companies regularly.

Downloading a fixed version of MATLAB 2012 provides immediate access to essential engineering tools. By following the installation steps—specifically choosing the offline installation method and utilizing the provided license file—you can ensure a stable, functional MATLAB environment for your academic or professional projects.

The Digital Preservation of Logic: Why We Still Search for MATLAB 2012 Introduction: The Ghost in the Research Machine

Below is a guide on how to download older versions legally and how to use

Change the date to a far-future date, e.g.: INCREMENT MATLAB MLM 2012.1208 31-dec-2099 ...

Follow these steps carefully to install the fixed MATLAB 2012 software. 1. Download and Extract