A maintenance system in which a user work made during a maintenance work is not lost is provided. Specifically, a user computing machine includes: a user data determination section determining, in a case that a name of a file received from a software update service is the same as a name of a file included in a VM that a user uses, whether the file included in the VM that the user uses is data created by the user; and a VM merge section copying a file except user data into the VM that the user uses in the received files by calling the user data determination section.