How can I get the list of input sources shown when switching between input sources?

I cannot get it to show on another MacBook.

I'm expecting the list to be shown when I press Control+Space.

The issue is that often conflicts exist between the shortcuts used for changing Input Sources and those used for showing the Spotlight search field.

To check/change these, follow these steps:

1. Go to Apple > System Preferences
2. Select the Keyboard preference pane
3. Select the Shortcuts tab
4. In the list at left, if you notice a warning icon next to either or both the Spotlight and Input Sources options, then you know you've got a conflict. If so,
   • you can select Spotlight on the left to remove the ticks from the checkboxes, or
   • you can set new shortcuts by clicking the current shortcut and then pressing the new key combination you want to use.

Note: Obviously you can change either or both sets of shortcuts to suit your needs, and you may need to do this on either or both Macs.