Garry Kasparov lost to a Computer playing 4. ... Nd7. Granted it was a Long time ago but yeah, it left a gaping hole in confidence for alot of people, including me.
Caro-Kann Theory 4..Nd7 Ideas and side lines

indeed taking IM phren's line; cool there is no fooking advantage after 6. Ng5 ~but things become alittle dicey after white plays instead 6. Nxf6 Nxf6 7. c3[!] Qc7 8. Ne2 e6 9. Qd3 b6 10. Bf4 Bd6 11. Qg3 Bxf4 12. Nxf4 Bb7 13. a4 a5 and white has a slight edge in the game Morozevich-Adams, Madrid 1996

even after 7. ... Nb6 8. Bd3 h6[!] 9. N5f3 c5 10. dxc5 (or 10. Be3~Svidler-Karpov) the game is unclear & up for grabs.

Garry Kasparov lost to a Computer playing 4. ... Nd7. Granted it was a Long time ago but yeah, it left a gaping hole in confidence for alot of people, including me.
Kasparov misplayed the opening, unfortunately.
(Karpov would've seen Nxe6 coming a mile away.)

In fact, during my brief stint of the Caro-Kann, I happened to play 4...Nd7 myself. The reason I quit the Caro has nothing to do with 3.Nc3.
What was the reason, if you don't mind me asking?

Garry Kasparov lost to a Computer playing 4. ... Nd7. Granted it was a Long time ago but yeah, it left a gaping hole in confidence for alot of people, including me.
Kasparov misplayed the opening, unfortunately.
(Karpov would've seen Nxe6 coming a mile away.)
Haha I 100 % agree

In fact, during my brief stint of the Caro-Kann, I happened to play 4...Nd7 myself. The reason I quit the Caro has nothing to do with 3.Nc3.
What was the reason, if you don't mind me asking?
It is 2-fold.
1) The advance lines with 4.h4 and the Fantasy Variation gave me problems. The former I still have problems understanding. The latter I get good results with White, which means I must have some concept behind the line, but must be missing something crucial for Black as otherwise everyone would play it and the Caro would be refuted, which clearly it is not!
2) While I shifted to 1...e5 then as my "secondary defense", once the pandemic hit and I was playing mostly correspondence, I realized that there was no need to play multiple defenses to diversify the positions I get to avoid playing like a robot and making silly blunders when White does something unusual. The answer is diversify within your primary opening! So now, instead of playing the French and Caro or French and Petroff or French and Taimanov Sicilian, it is now a simple fact that I ALWAYS answer 1.e4 with 1...e6, and virtually anything other than 2.Qe2 with 2...d5, and deviate after that based on mood. For example, if 3.Nd2, I'll go 3...c5 w/ 5...Nf6, 3...c5 w/ 5...Nc6, 3...Be7, 3...Nf6 w/ 6...b6 instead of 6...Nc6 (I hate the main Closed lines for Black), or 3...dxe4. If 3.Nc3, I'll play the Winawer with 7...Qc7, 7...cxd4, 7...O-O, 7...Kf8, and 7...Nf5 against 7.Qg4. Then you have the other 7th moves (I play 7.h4 as White). Then I also play 3...Nf6 (both Classical and McCutchen along with Steinitz) and 3...dxe4. So no need to diversify any more at move 1! Therefore, once again, no more Caro for me!

It is 2-fold.
1) The advance lines with 4.h4 and the Fantasy Variation gave me problems. The former I still have problems understanding. The latter I get good results with White, which means I must have some concept behind the line, but must be missing something crucial for Black as otherwise everyone would play it and the Caro would be refuted, which clearly it is not!
2) While I shifted to 1...e5 then as my "secondary defense", once the pandemic hit and I was playing mostly correspondence, I realized that there was no need to play multiple defenses to diversify the positions I get to avoid playing like a robot and making silly blunders when White does something unusual. The answer is diversify within your primary opening! So now, instead of playing the French and Caro or French and Petroff or French and Taimanov Sicilian, it is now a simple fact that I ALWAYS answer 1.e4 with 1...e6, and virtually anything other than 2.Qe2 with 2...d5, and deviate after that based on mood. For example, if 3.Nd2, I'll go 3...c5 w/ 5...Nf6, 3...c5 w/ 5...Nc6, 3...Be7, 3...Nf6 w/ 6...b6 instead of 6...Nc6 (I hate the main Closed lines for Black), or 3...dxe4. If 3.Nc3, I'll play the Winawer with 7...Qc7, 7...cxd4, 7...O-O, 7...Kf8, and 7...Nf5 against 7.Qg4. Then you have the other 7th moves (I play 7.h4 as White). Then I also play 3...Nf6 (both Classical and McCutchen along with Steinitz) and 3...dxe4. So no need to diversify any more at move 1! Therefore, once again, no more Caro for me!
Makes sense. And thanks for explaining.
Chess is difficult enough without having to juggle multiple defenses, I agree. It's completely reasonable to narrow things down, and to keep the diversity within a specific opening umbrella.
I would play an e6+d5 structure against most everything, for simplicity's sake, but I'm not a fan of playing the black side of the Advance French. There's nothing wrong with it, of course (and for many French players, counterpunching against the Advance is one of their favorite variations).
I just enjoy playing the Caro-Kann against the Advance more ... mostly for reasons of personal preference.

In fact, during my brief stint of the Caro-Kann, I happened to play 4...Nd7 myself. The reason I quit the Caro has nothing to do with 3.Nc3.
What was the reason, if you don't mind me asking?
It is 2-fold.
1) The advance lines with 4.h4 and the Fantasy Variation gave me problems. The former I still have problems understanding. The latter I get good results with White, which means I must have some concept behind the line, but must be missing something crucial for Black as otherwise everyone would play it and the Caro would be refuted, which clearly it is not!
2) While I shifted to 1...e5 then as my "secondary defense", once the pandemic hit and I was playing mostly correspondence, I realized that there was no need to play multiple defenses to diversify the positions I get to avoid playing like a robot and making silly blunders when White does something unusual. The answer is diversify within your primary opening! So now, instead of playing the French and Caro or French and Petroff or French and Taimanov Sicilian, it is now a simple fact that I ALWAYS answer 1.e4 with 1...e6, and virtually anything other than 2.Qe2 with 2...d5, and deviate after that based on mood. For example, if 3.Nd2, I'll go 3...c5 w/ 5...Nf6, 3...c5 w/ 5...Nc6, 3...Be7, 3...Nf6 w/ 6...b6 instead of 6...Nc6 (I hate the main Closed lines for Black), or 3...dxe4. If 3.Nc3, I'll play the Winawer with 7...Qc7, 7...cxd4, 7...O-O, 7...Kf8, and 7...Nf5 against 7.Qg4. Then you have the other 7th moves (I play 7.h4 as White). Then I also play 3...Nf6 (both Classical and McCutchen along with Steinitz) and 3...dxe4. So no need to diversify any more at move 1! Therefore, once again, no more Caro for me!
If you feared the tal just play 3…c5

If you feared the tal just play 3…c5
...and?
4.dxc5 e6 5.a3 forces Black to play several accurate move to equalize, but I would be more concerned about the practical 5.Qg4, after which Black has to play something like 5...h5 to get the pawn back, and then he has to play "computer chess" with his king in the center.
3...c5 is "good" because the computers like it. The natural human reaction is certainly enough 3...Bf5.
indeed. As a CK player, I agree with TF, but also with the NM Ry! 🤔