Very-Large Scale Systems (VLSS) play a powerful role in shaping what anorganization does and can do in a practical sense. VLSS are deeply embedded in anorganization's procedures, business plans, and strategies. These systems evolve overlong periods of time, often not according to some rational plan, and for a limitedtime they provide a significant competitive advantage over other firms. In the longrun, however, VLSS become strategic liabilities and must be rebuilt.Many organizations experience great difficulty rebuilding VLSS. Indeed,most organizations attempt to avoid rebuilding VLSS until the last possible moment.Often, the organization is in a state of crisis, a strategic transition. Because of thecomplexity and size of VLSS, existing methodologies often are not helpful. To makematters worse, the typical management incentive structure discourages rebuildingVLSS.In a typical VLSS effort, participants soon discover that they must rebuild theorganization in order to take full advantage of new technologies. A majororganizational engineering effort is often required. Senior management as well assystems management routinely underestimate the complexity of the task beforethem. Consequently, large errors are made in estimating costs and time.Drawing on research in both the private and public sector, this paperexamines why VLSS fail, why are VLSS so difficult to rebuild, what are the strategyoptions, and how can senior management guide the rebuilding process