# Change General settings in CotEditor on Mac

Use General settings in CotEditor to choose how to handle documents, save, and more.

To change these settings in the CotEditor app on your Mac, choose CotEditor > Settings, then click General.

Option | Description
--- | ---
Reopen windows from last session | On starting up, automatically opens the documents that were opened when quitting last time. This change is first applied at the next application launch and is reflected at the next launch after that.
When nothing else is open | To change the behavior when you launch CotEditor and you had no window already open, click the pop-up menu, then choose an option: Create New Document: Create a new blank document. Show Open Dialog: Show the open dialog to select a document to open. Do Nothing: Just activate the application and do nothing.
Enable Auto Save with Versions | Automatically save documents to your file constantly while editing. This option also makes Versions available, the system feature allowing you to go back to previous versions, as well as modify document name or location from the window title bar. Even if the option is turned off, CotEditor creates backup covertly for unexpected quit.
When document is changed by another application | Choose the behavior when the document file was updated by another application while it is opened in CotEditor. Keep CotEditor’s edition: Do nothing and keep CotEditor’s edition. CotEditor may ask whether overwrite the file that was changed by another application first when you save the document. Ask how to resolve: Show a dialog when the file was changed by another application so that you can choose between keeping CotEditor’s edition or reverting to the latest file. Update to modified edition: Update the editor’s text to the latest version silently when the file was changed by another application. Take notice that the undo history will also be cleared after updating.
Dialog warnings | Manage whether showing a warning dialog when problems are found in the document. See Manage warnings for each warning items.
Command-line tool | This section shows the installation status of the `cot` command-line tool. See Work with cot command for details.

Software Update (only on non-AppStore ver.)
Option | Description
--- | ---
Check for updates automatically | Check the existence of a new version through the internet automatically on launch. Then if a new one has been released, CotEditor notifies the information on a dialog.
Include prereleases | Notify also about releases of prerelease versions (beta versions). Take notice that prerelease versions can be unstable.

## See also

- Change settings