ChemDraw, Save, autosave, macOS, upgrade
When the autosave feature is enabled in MacOS, the system will not prompt you to save your document after closing it.
This is a feature from the Operating System.
1. To turn off Auto Save, launch System Preferences by clicking or tapping its icon in the Dock, or selecting System Preferences from the Apple menu.
2. Select the General preference pane.
3. Place a checkmark in the checkbox labeled Ask to keep changes when closing documents.
This will not turn off the file versioning system, although new versions will only be added for a file when you manually perform a save.