Abstract: The invention relates to a method and system for migrating data stored in a second computing system to a first computing system, particularly wherein the first computing system is a local file system and the second computing system is a backup file system storing files to be transferred to the local file system. The method comprises pre-allocating a primary file matching a corresponding secondary file the second computing system. In response to receiving a read request for a data block not yet stored in the primary file, method comprises retrieving the requested data block from the secondary file and storing same locally in the primary file such that it is usable in the local system. The primary file is automatically populated with data blocks from the secondary file until it is complete in respect of data blocks stored. The system substantially carries out the method of the invention.