Follow these steps to re-enable screenshot hotkeys on your Mac:
- Click Apple Menu > System Preferences.
- Click Keyboard in the System Preferences window. If your list looks different, type Keyboard in the search pane in the top right of the System Preferences window.
- Click the Shortcuts tab in the Keyboard window.
- Click Screen Shots in the list on the left of the Shortcuts tab.
- Check the boxes for all shortcuts you wish to re-enable.
- Close the window.