user7035: I just downloaded Stockfish, input a couple games, and saved them. They look like generic documents when I save and try to open. I just used the default Save function in Stockfish. Finder tells me they are .pgn documents. The problem is when I try to open I get this message: 
The document “example” could not be opened. Stockfish cannot open files of this type.
So what are the steps to save a game so that it can be opened later? 
(This question is so basic that I couldn't find any forum help on it so I guess I'm the only one dumb enough.)

user9926: I don't own a Mac, so I can't test these myself (and the solutions' efficacy might vary with software/firmware), but here are some solutions that have worked for others:
Per ref. 1:

Note: Invalid moves in the PGN file seem to prevent the file's opening.
At the end of every line in the PGN file, add a space. Then they should open with the current version of Stockfish for Mac.
Open the PGN files with a text editor and convert the line endings to CRLF (Windows line endings). Then they should open with the current version of Stockfish for Mac.
Compile and run the latest Stockfish for Mac development version from GitHub. This has the fix.

Per ref. 2:

If you're playing a chess variant, then add a FEN tag to the PGN file (if there isn't one there already).

FEN tag example:

OTHER TAGS GO HERE
  [FEN "brkbqnrn/pppppppp/8/8/8/8/PPPPPPPP/BRKBQNRN w KQkq"]
  [SetUp "1"]
MOVES GO HERE


References:

http://support.stockfishchess.org/discussions/problems/3362-pgn-files-not-opening-stockfish-for-mac 
https://www.reddit.com/r/chess/comments/2w9zgf/how_do_i_use_stockfish_with_chess960/ 


7035: <p>I just downloaded Stockfish, input a couple games, and saved them. They look like generic documents when I save and try to open. I just used the default Save function in Stockfish. Finder tells me they are .pgn documents. The problem is when I try to open I get this message: </p>

<p>The document “example” could not be opened. Stockfish cannot open files of this type.</p>

<p>So what are the steps to save a game so that it can be opened later? 
(This question is so basic that I couldn't find any forum help on it so I guess I'm the only one dumb enough.)</p>
 9926: <p>I don't own a Mac, so I can't test these myself (and the solutions' efficacy might vary with software/firmware), but here are some solutions that have worked for others:</p>

<p>Per ref. 1:<br></p>

<ul>
<li><p><i>Note: Invalid moves in the PGN file seem to prevent the file's opening.</i><br></p></li>
<li><p>At the end of every line in the PGN file, add a space. Then they should open with the current version of Stockfish for Mac.<br></p></li>
<li>Open the PGN files with a text editor and convert the line endings to CRLF (Windows line endings). Then they should open with the current version of Stockfish for Mac.<br></li>
<li>Compile and run the latest Stockfish for Mac development version from GitHub. This has the fix.<br></li>
</ul>

<p>Per ref. 2:<br></p>

<ul>
<li>If you're playing a chess variant, then add a FEN tag to the PGN file (if there isn't one there already).</li>
</ul>

<p><i>FEN tag example:</i></p>

<blockquote>
  <p>OTHER TAGS GO HERE
  [FEN "brkbqnrn/pppppppp/8/8/8/8/PPPPPPPP/BRKBQNRN w KQkq"]
  [SetUp "1"]</p>
  
  <p>MOVES GO HERE</p>
</blockquote>

<hr>

<p><b>References:</b></p>

<ol>
<li><a href="http://support.stockfishchess.org/discussions/problems/3362-pgn-files-not-opening-stockfish-for-mac" rel="nofollow">http://support.stockfishchess.org/discussions/problems/3362-pgn-files-not-opening-stockfish-for-mac</a> </li>
<li><a href="https://www.reddit.com/r/chess/comments/2w9zgf/how_do_i_use_stockfish_with_chess960/" rel="nofollow">https://www.reddit.com/r/chess/comments/2w9zgf/how_do_i_use_stockfish_with_chess960/</a> </li>
</ol>
