user15396: I have gotten back to learning chess, and I started using the chess game program on my 2015 MacBook Pro. Last night I wanted to castle, but it would not allow me to do so. I was white by the way. Later on, I saw that black was allowed to castle.
Is there some reason why the MacBook Pro Chess game program does not allow for castling? Or is there a rule about castling as white I am yet to learn?
I moved my King over to the Rook - nothing. I then moved my Rook over to the King, again nothing. The pieces went back to their original place.

user15396: I am going to accept DMs answer because it has so much good information on Chess rules, but to be clear my question was in regards to how does the MacBook Pro Chess game understand that you are trying to castle.
On my Windows 7 machine, you move the King to h1 and that's how it knows you are castling.
For future readers who run into similar problems where this does not work in their MacBook Pro Chess game, you need to move the King to g1 and at that point, your Macs Chess game understands you are castling and will move the Rook over to f1 for you.
At no point was I in check, so yes if you are in check, no attempt at castling will work. For Macs Chess game you cannot move the King to h1 where the Rook is, you have to move it to g1 to the left of the Rook and the Chess game will understand its castling and thereby move your Rook over to f1.
On Windows 7, the default behavior of the Chess game is you must move King over to h1 where the Rook is, it will understand it as castling and move the Rook over.

user12629: According to the rules of castling, you cannot castle if:

Your king has ever moved.
The rook you are castling with has ever moved.
Your king is currently in check.
Your king would be in check at the destination square.
Your king must cross through check.

Most likely, one of these factors was the reason you couldn't castle.
If none of these are the case, then perhaps dropping the king on the rook is the problem. The program might want you to drop the king on its destination square.

15396: <p>I have gotten back to learning chess, and I started using the chess game program on my 2015 MacBook Pro. Last night I wanted to castle, but it would not allow me to do so. I was white by the way. Later on, I saw that black was allowed to castle.</p>

<p>Is there some reason why the MacBook Pro Chess game program does not allow for castling? Or is there a rule about castling as white I am yet to learn?</p>

<p>I moved my King over to the Rook - nothing. I then moved my Rook over to the King, again nothing. The pieces went back to their original place.</p>
 15396: <p>I am going to accept DMs answer because it has so much good information on Chess rules, but to be clear my question was in regards to how does the MacBook Pro Chess game understand that you are trying to castle.</p>

<p>On my Windows 7 machine, you move the King to h1 and that's how it knows you are castling.</p>

<p>For future readers who run into similar problems where this does not work in their MacBook Pro Chess game, you need to move the King to g1 and at that point, your Macs Chess game understands you are castling and will move the Rook over to f1 for you.</p>

<p>At no point was I in check, so yes if you are in check, no attempt at castling will work. For Macs Chess game you cannot move the King to h1 where the Rook is, you have to move it to g1 to the left of the Rook and the Chess game will understand its castling and thereby move your Rook over to f1.</p>

<p>On Windows 7, the default behavior of the Chess game is you must move King over to h1 where the Rook is, it will understand it as castling and move the Rook over.</p>
 12629: <p>According to the rules of castling, you cannot castle if:</p>

<ul>
<li>Your king has ever moved.</li>
<li>The rook you are castling with has ever moved.</li>
<li>Your king is currently in check.</li>
<li>Your king would be in check at the destination square.</li>
<li>Your king must cross through check.</li>
</ul>

<p>Most likely, one of these factors was the reason you couldn't castle.</p>

<p>If none of these are the case, then perhaps dropping the king on the rook is the problem. The program might want you to drop the king on its destination square.</p>
