1. A method of modifying a virtual application configuration used to configure a virtualized version of an application, the method comprising: creating, with a computing system, a read-only first virtualized application file using the virtual application configuration; executing the first virtualized application file, the executing first virtualized application file storing information identifying modifications to data stored in the first virtualized application file in a memory location; reading, with the computing system, the information stored in the memory location; and creating, with the computing system, a modified virtual application configuration by merging the information read from the memory location into the virtual application configuration, the modified virtual application configuration being usable by the computing system to create a read-only second virtualized application file.