A method for enabling a distributed computing system to tolerate system faults during the execution of a client process. The method includes instantiating an execution environment relating to the client process; executing instructions within the execution environment, the instructions causing the execution environment to issue further instructions to the distributing computing system, the further instructions relating to actions to be performed with respect to data stored on the distributed computing system. An object interface proxy receives the further instructions and monitors the received to determine if the execution environment is in a desired save-state condition; and, if so, save a current state of the execution environment in a data store.