In dispersed, multinational enterprises, complex integrations of information systems are a commonly hated threat as they render difficult fundamental changes of IT structures and standards embedded therein. This paper explores how integrations can turn into a burden and how thereby a company's technology platform can lock-in to a local optimum. We conceptualize information system architectures - a company's set of information systems and integrations - as networks. Based thereupon, we suggest a network model of path building that formalizes architectural growth processes and on-top technology adoptions, as when new systems attach preferentially to important hubs. Agent-based simulations give insights into how different growth parameters, i.e. new systems' degree of integration and preferentiality, increase the architecture's complexity and can reinforce predominant architectural patterns, such as "islands of shared technologies". We contrast the simulation results to empirical data that show the emergence of a fragmented IT landscape in a regionally-dispersed recycling company.