user8673: Normally, using engines for any given opening I can find ways for White to maintain a slight edge into the middle game. By a "slight edge" I mean an evaluation of around +0.20
The exception to this is the Classical French (and Steinitz), where it seems like every line Black has at least equality and most lines lead to an edge for Black!
For example, in his book on the French, Psakhis says that after 1. e4 e6 2. d4 d5 3. Nc3 Nf6 4. Bg5 Be7 5. e5 Nfd7 6. h4 0-0?! is dubious for Black after 7. Bd3. However, the engine shows that not only is not dubious for Black, but Black has the advantage after 7...c5!
This is just one example. No matter what line I try, Black always seems to get at least equality.
Even more scary is that not only is Black always getting equality, but White seems to have a lot more ways to go wrong than Black in many of the lines.
Is there any line in the Classical where White can retain a pull?
I am using Komodo 10 as my engine.

user11609: Very good question! I was looking at Negi's book on e4 and in French in Nc3 Bb4 line the engine evaluated soooo many lines better for black that it could drive me crazy. In Qg4 O-O system (instead of sacrificing g7+h7) it shows advantages only for black even on very high depths. Similarly the immediate Nf6 e5 and your Nf6 Bg5. Was quite frustrated by this, but than I checked correspondence games in some of the lines and white was often one with clearly the better results. But it stood often on insane sacrifices, precise maneuvers no human could ever find. So you must make the best assessment possible how each line fits for human and your play, whether it is more difficult to play for white or for black. Often one side gets the objective advantage while the other side gets desired type of position, which is both valuable. No popular line can be both bad and unpractical. In my particular example the final truth was on white's side, but missing one move can hurt the evaluation to what engine thinks about the position not seeing the precise continuation. I didn't very enjoy what I saw as defence had too obvious moves while attack was too hard to play good. Engine doesn't understand human needs for position so it's use in specific lines is limited. Those comes to my mind.
French
g5 b4 racing in Najdorf
Poisoned pawn in Sicilian
KID
for the main theoretical ones
Many gambit and tricky lines are of course also misunderstood by chess engines as they expect perfect play from both sides which never happen. 

user4588: From my experience it can be dangerous to analyze openings with a single engine only. Adding an extra engine can be very helpful, as it has a different evaluation function. Stockfish is open source and probably at least as strong as Komodo (according to the CCRL).
Futhermore, when studying an opening, it is also important to check game databases and opening books.
As far as I know, the current theoretical status of the French defence is that it is a sound opening, with good chances to obtain equality with black, but white can try to fight for a small advantage.
In the line you give, 1.e4 e6 2.d4 d5 3.Nc3 Nf6 4.Bg5 Be7 5.e5 Nfd7 6.h4 0-0 7.Bd3 c5, it seems that white can force a draw: 8.Qh5 g6 9.Qh6 cxd4 10.Nf3 Nxe5 11.Nxe5 dxc3 12.Nxg6 fxg6 13.Bxg6 hxg6 14.Qxg6+. This is exactly what happened in several games, e.g. Anton Guijarro-Forcen Esteban.
Instead, white can try to obtain an advantage with 7.Qg4, which was played for the first time in Hebden-Gurevich. The immediate threat is Bh6 and after 7....f5, white is probably better after 8.Bxe7 Qxe7 9.Qg5.
Therefore, the main line is 7....f6 (Hector-So), where white can choose between the greedy 8.Qxe6+ (Hector-Matthiesen) or the aggressive 8.Bd3. After the latter, white seems to have a very dangerous attack, e.g. 8....Rf7 9.Nf3 c5 10.Nxd5 exd5 11.e6 and 9....Nc6 10.Bg6! hxg6 11.h5 gxh5 12.Qxh5 Rf8 13.Nxd5.


      [StartPly "12"]

      [FEN ""]
      1.e4 e6 2.d4 d5 3.Nc3 Nf6 4.Bg5 Be7 5.e5 Nfd7 6.h4 O-O 7.Qg4 (7.Bd3 c5 8.Qh5 g6 9.Qh6 cxd4 10.Nf3 Nxe5 11.Nxe5 dxc3 12.Nxg6 fxg6 13.Bxg6 hxg6 14.Qxg6+) f6 (7...c5 8.Bh6) (7...Kh8 8.Nf3 c5 9.Bd3) (7...Re8 8.Bh6 Bf8 9.h5) (7...f5 8.Bxe7 Qxe7 9.Qg5 Qb4 10.O-O-O) 8.Bd3 (8.Qxe6+ Kh8 9.exf6 Nxf6 10.Qe2) Rf7 (8...fxg5 9.Bxh7+) 9.Nf3 Nc6 (9...c5 10.Nxd5 exd5 11.e6) 10.Bg6! hxg6 11.h5 gxh5 12.Qxh5 Rf8 13.Nxd5




user11629: An evaluation of +0.2 is just noise and nothing like a "slight edge". Another engine might very well give you -0.2 or so. I would not be overly concerned by such evaluation. 
When analyzing opening lines, much more important is the character of the position: whether you like it, whether it  gives you winning or drawing chances (depending on requirement), whether it is easy to play for you (and difficult for your opponent), etc. All of these are difficult to assess automatically with a computer and require you to look at it. That's why GM spend so much time on openings and don't just have their computers running looking for the line with the highest evaluation.

8673: <p>Normally, using engines for any given opening I can find ways for White to maintain a slight edge into the middle game. By a "slight edge" I mean an evaluation of around +0.20</p>

<p>The exception to this is the Classical French (and Steinitz), where it seems like every line Black has at least equality and most lines lead to an edge for Black!</p>

<p>For example, in his book on the French, Psakhis says that after 1. e4 e6 2. d4 d5 3. Nc3 Nf6 4. Bg5 Be7 5. e5 Nfd7 6. h4 0-0?! is dubious for Black after 7. Bd3. However, the engine shows that not only is not dubious for Black, but Black has the advantage after 7...c5!</p>

<p>This is just one example. No matter what line I try, Black always seems to get at least equality.</p>

<p>Even more scary is that not only is Black always getting equality, but White seems to have a lot more ways to go wrong than Black in many of the lines.</p>

<p>Is there any line in the Classical where White can retain a pull?</p>

<p>I am using Komodo 10 as my engine.</p>
 11609: <p>Very good question! I was looking at Negi's book on e4 and in French in Nc3 Bb4 line the engine evaluated soooo many lines better for black that it could drive me crazy. In Qg4 O-O system (instead of sacrificing g7+h7) it shows advantages only for black even on very high depths. Similarly the immediate Nf6 e5 and your Nf6 Bg5. Was quite frustrated by this, but than I checked correspondence games in some of the lines and white was often one with clearly the better results. But it stood often on insane sacrifices, precise maneuvers no human could ever find. So you must make the best assessment possible how each line fits for human and your play, whether it is more difficult to play for white or for black. Often one side gets the objective advantage while the other side gets desired type of position, which is both valuable. No popular line can be both bad and unpractical. In my particular example the final truth was on white's side, but missing one move can hurt the evaluation to what engine thinks about the position not seeing the precise continuation. I didn't very enjoy what I saw as defence had too obvious moves while attack was too hard to play good. Engine doesn't understand human needs for position so it's use in specific lines is limited. Those comes to my mind.</p>

<p>French
g5 b4 racing in Najdorf
Poisoned pawn in Sicilian
KID</p>

<p>for the main theoretical ones</p>

<p>Many gambit and tricky lines are of course also misunderstood by chess engines as they expect perfect play from both sides which never happen. </p>
 4588: <p>From my experience it can be dangerous to analyze openings with a single engine only. Adding an extra engine can be very helpful, as it has a different evaluation function. <a href="https://stockfishchess.org/" rel="nofollow noreferrer">Stockfish</a> is open source and probably at least as strong as Komodo (according to the <a href="http://www.computerchess.org.uk/ccrl/404/" rel="nofollow noreferrer">CCRL</a>).
Futhermore, when studying an opening, it is also important to check game databases and opening books.</p>

<p>As far as I know, the current theoretical status of the French defence is that it is a sound opening, with good chances to obtain equality with black, but white can try to fight for a small advantage.</p>

<p>In the line you give, 1.e4 e6 2.d4 d5 3.Nc3 Nf6 4.Bg5 Be7 5.e5 Nfd7 6.h4 0-0 7.Bd3 c5, it seems that white can force a draw: 8.Qh5 g6 9.Qh6 cxd4 10.Nf3 Nxe5 11.Nxe5 dxc3 12.Nxg6 fxg6 13.Bxg6 hxg6 14.Qxg6+. This is exactly what happened in several games, e.g. <a href="https://chess-db.com/public/game.jsp?id=2285525.2288230.78551296.28085" rel="nofollow noreferrer">Anton Guijarro-Forcen Esteban</a>.</p>

<p>Instead, white can try to obtain an advantage with 7.Qg4, which was played for the first time in <a href="http://www.chessagain.com/index.php?cnt=5&amp;sub=3&amp;game=21426&amp;type=5" rel="nofollow noreferrer">Hebden-Gurevich</a>. The immediate threat is Bh6 and after 7....f5, white is probably better after 8.Bxe7 Qxe7 9.Qg5.
Therefore, the main line is 7....f6 (<a href="http://www.chessgames.com/perl/chessgame?gid=1624937" rel="nofollow noreferrer">Hector-So</a>), where white can choose between the greedy 8.Qxe6+ (<a href="http://www.chessgames.com/perl/chessgame?gid=1638893" rel="nofollow noreferrer">Hector-Matthiesen</a>) or the aggressive 8.Bd3. After the latter, white seems to have a very dangerous attack, e.g. 8....Rf7 9.Nf3 c5 10.Nxd5 exd5 11.e6 and 9....Nc6 10.Bg6! hxg6 11.h5 gxh5 12.Qxh5 Rf8 13.Nxd5.</p>

<pre>
<code>
      [StartPly "12"]

      [FEN ""]
      1.e4 e6 2.d4 d5 3.Nc3 Nf6 4.Bg5 Be7 5.e5 Nfd7 6.h4 O-O 7.Qg4 (7.Bd3 c5 8.Qh5 g6 9.Qh6 cxd4 10.Nf3 Nxe5 11.Nxe5 dxc3 12.Nxg6 fxg6 13.Bxg6 hxg6 14.Qxg6+) f6 (7...c5 8.Bh6) (7...Kh8 8.Nf3 c5 9.Bd3) (7...Re8 8.Bh6 Bf8 9.h5) (7...f5 8.Bxe7 Qxe7 9.Qg5 Qb4 10.O-O-O) 8.Bd3 (8.Qxe6+ Kh8 9.exf6 Nxf6 10.Qe2) Rf7 (8...fxg5 9.Bxh7+) 9.Nf3 Nc6 (9...c5 10.Nxd5 exd5 11.e6) 10.Bg6! hxg6 11.h5 gxh5 12.Qxh5 Rf8 13.Nxd5

</code>
</pre>
 11629: <p>An evaluation of +0.2 is just noise and nothing like a "slight edge". Another engine might very well give you -0.2 or so. I would not be overly concerned by such evaluation. </p>

<p>When analyzing opening lines, much more important is the character of the position: whether you like it, whether it  gives you winning or drawing chances (depending on requirement), whether it is easy to play for you (and difficult for your opponent), etc. All of these are difficult to assess automatically with a computer and require you to look at it. That's why GM spend so much time on openings and don't just have their computers running looking for the line with the highest evaluation.</p>
