Save and Revert Changes
JetBrains Rider automatically saves changes that you make in your files. Saving is triggered by various events, such as compiling, running, debugging, performing version control operations, closing a file or a project, or quitting the IDE. Saving files can be also triggered by third-party plugins.
Most of the events that trigger auto-save are predefined and cannot be configured, but you can be sure that changes will not be lost and you can find all of them in local history.
Configure autosave behavior
Press Ctrl+Alt+S to open IDE settings and select Appearance and Behavior | System Settings.
Under Autosave, configure the following options:
Save files when switching to a different application
Save files is the IDE is idle for N seconds
Mark files with unsaved changes
Press Ctrl+Alt+S to open IDE settings and select Editor | General | Editor Tabs.
Select the Mark modified (*) checkbox.