A method for use in an endpoint device having a local storage system, to seamlessly access files in a cloud storage system. The method comprises: receiving, by a virtual file system driver, a request from a program running on the endpoint to access data within a file in a unified virtual file system, the local storage system being configured to maintain files, each file therein being in a stub or non-stub state and also being in a synchronized or a non-synchronized state, retrieving a portion of the file containing some of the requested data from the cloud storage system when the file is in a stub state; making the retrieved portion of the file available to the program upon being successfully retrieved; and maintaining the file in the non-stub and synchronized state for a period of time based on a determination that the file should be synchronized locally.