If you are looking to learn the software or need it for a specific project, there are better, safer alternatives to searching for a crack:

Using unlicensed software for commercial projects can result in massive fines and legal action from ALLPLAN. Furthermore, most modern BIM software has "phone home" telemetry that alerts developers when an illegal license is being used. Legitimate Ways to Access SDS/2

Modern software delivery has moved toward subscription-based pricing, making the entry cost for detailing software much lower than the traditional perpetual license fees of the past. Conclusion

SDS/2 relies on frequent updates to maintain compatibility with updated Windows versions and other BIM software like Revit or Tekla. A cracked version is "frozen" in time and cannot access critical bug fixes.