1. A method for cross-operating systems execution of a legacy software application on a user computing device, comprising: responsive to a native application having been launched on the user computing device, executing, on a server, a virtualized cloud version of the legacy software application, wherein the legacy software application is compliant with a first operating system, the user computing device is compliant with a second operating system, and the first operating system and the second operating system are incompatible with each other; at the server, having the virtualized cloud version of the legacy software application act on inputs that were generated by the native application and that were transmitted to the server; at the server, rendering image outputs responsive to the virtualized cloud version of the legacy software application acting on the inputs; at the server, streaming the rendered image outputs to the user computing device to be displayed on the user computing device by the native application; and performing file system operations on a cloud storage service, the file system operations requested by at least one of the native application and the virtualized cloud version of the legacy software application, wherein the native application corresponds to the legacy software application and includes a set of permissions granted to a user of the computing device and an address of the server, and the virtualized cloud version of the legacy software application includes a user data file containing personalization and customization information of the user of the computing device.