It is a good practice to save your changes periodically while you work. You can save changes to your project as follows:
On the Quick Access toolbar at the top of the application, click the Save button
.Press Ctrl+S.
On the Project tab, click Save.
If you created a project with a template or opened an existing project, information stored in the project file (.d2mx) will be updated when the project is saved. This information includes:
Items stored in the project, such as maps and state of layers in the Contents pane
Connections to items, such as folders, databases, servers, toolboxes, locators, and custom styles
Saving the project does not require you to save spatial data edits that are in progress. Each of these environments has its own methods for saving changes and are separate from saving changes to the project.
To create a project file (.d2mx), on the Project tab, click Save As. This will allow you to browse to a location on disk and save the project as a newly named .d2mx file.