Technology is disclosed herein for resolving synchronization conflicts when synchronizing application state data between computing devices. According to at least one embodiment, a server detects a first set of application state data at a first computing device conflicting with a second set of application state data at a second computing device. The first and second sets of application state data represent application states of the same computer application running at the first and second computing devices, respectively. Accordingly, the first computing device presents a user interface prompting a user to choose a preferred set of application state data between the first and second sets of application state data. If the user chooses the second set of application state data as the preferred set, the first computing device uses the second set of application state data to overwrite the first set of application state data at the device.