In addition to the risks mentioned above, using a cracked license for Quartus II 6.1 can have specific consequences, including:

Even for very old versions like 6.1, Intel often provides a path for "Legacy" or "Web Edition" licenses that allow for legal, free use of the software for educational or hobbyist purposes. How to Get a Legal License for Legacy Quartus II

Quartus II software requires a license to activate its full features. The licensing model typically involves: