I want to change Command+Space combination to change keyboard layout to a Windows like Alt+Shift but the Lion's keyboard settings does not react when I assign that particular combination. It allows me to change it to a other combinations, however. I assume this is because Alt+Shift is already being used by some other program, but which one? How can I tell that and what can I do to override that setting?

1 Answer 1


I don't think you can use alt + shift for anything by itself. It is used for all kinds of special characters in combination with a letter key.

How Mac OS X lets you toggle between different international language keyboard layouts

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How Mac OS X uses the "Option" key as a "dead key" to enable typing diacriticals for Western European languages in the US keyboard layout.

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Here is where a conflict may arise.

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  • 2
    The Alt-key, or Option key as we call it, on the Mac, is used in conjunction with letter keys to make letters with diacriticals, such as é, ü, ø, ñ and ç. Therefore I suspect it is not normally possible to remap this key. Sounds like a job for Ukelele, if it is possible at all. goo.gl/iFLae
    – user9290
    Commented Aug 21, 2011 at 2:11
  • Thanks! So is it correct to assume that this Command + Space combination has been used for that purpose for a long time? Commented Aug 21, 2011 at 2:12
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    The Option key has been used to type diacriticals since the first Mac in 1984.
    – user9290
    Commented Aug 21, 2011 at 2:14
  • Command-Space and Option-Command-Space are the reserved key combinations to advance from one keyboard layout to the next. I'll add a screen shot or two above.
    – user9290
    Commented Aug 21, 2011 at 2:17

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