A new Star Wars canon novel confirms Yoda did recognize R2-D2 when the astromech droid arrived on Dagobah with Luke Skywalker. Star Wars confirms Yoda recognized R2-D2 on Dagobah in The Empire Strikes Back.
However, while Yoda acts as though he had never met R2-D2 before, the Star Wars prequel trilogy, released decades later, revealed that Yoda was already well acquainted with the famous astromech droid.
They did meet. But to be fair, it's quite possible Yoda wouldn't have recognized R2 regardless of the circumstances. There are a LOT of droids out there in Star Wars, and probably a lot of R2-D2's too.
Yes. In the last episodes of season 6 of Star Wars: The Clone Wars, R2-D2 actually visits Dagobah with Yoda during Yoda's trials to learn the art of maintaining one's individuality in the cosmic force after death. So in answer to this question, yes, R2-D2 and Yoda have met before. So he did remember!
R2-D2, the indomitable droid and mainstay of the Star Wars series, may be responsible for one more incredible feat: saving Grogu.
Canon characters, such as Anakin Skywalker, whose relationship with R2-D2 is one of the best in the whole series, Rey, Poe Dameron, Hera Snydulla and Kazuda Xiono are fluent in the droid language. And after spending decades with R2 himself, Luke Skywalker is also able to understand him.
Obi-Wan Was Pretending He Didn't Know R2-D2
The base assumption of why Obi-Wan doesn't remember R2-D2 -- in light of the prequels -- is that Obi-Wan is feigning ignorance in A New Hope to downplay the importance of the droid's arrival.
Yes, he did. In the comic Thank the Maker, Darth Vader comes into possession briefly of 3PO's disassembled head while on Cloud City.
Nope. Only C-3PO gets his memory wiped.
After the battle, R2-D2 and C-3PO were the sole witnesses to the marriage of Anakin Skywalker and Padmé Amidala in Lake Country. After this Padmé gave ownership of R2 to Anakin while she kept 3PO.
Since Obi-Wan and Anakin often fought together, Obi-Wan was friends with R2-D2 as well. This means that although R2-D2 might not have immediately recognized Obi-Wan on Tatooine due to his age, Obi-Wan should have recognized the droid.
R2-D2 was present when Padmé gave birth to Leia and Luke, so he knew Luke was Anakin's son – but what he didn't know was that Anakin became Darth Vader. In addition to that, Anakin's fall was surely a painful event in R2-D2's life, one that he definitely wouldn't like to remember or even talk about.
Binary. Binary, or Droidspeak, is made up of beeps and whistles. The language is “spoken” by droids such as R2-D2 and BB-8.
C-3PO, his robot companion, could speak 6-million languages including excellent English with a hint of a British accent and all R2-D2 could muster were beeps and whistles. Clearly the technology was there to let him speak, but whoever designed him intentionally decided to stick with the beeps and whistles.
Yes. There's a fair bit of evidence throughout the franchise that humans can learn to understand binary. Anakin, Hera, Luke, and Rey all specifically and clearly understand exactly what the astromech droids are saying. And Ahsoka.
No. There is a non-canon comic of Darth Vader finding C-3PO's dismantled body at Bespin which gives an interesting, albeit blatantly non-canon look at what Vader might think. But to my knowledge there's no evidence at all that either of the droids ever met Darth Vader nor recognized him.
Late in the film, Darth Vader does not recognize C-3PO who is in Cloud City with Han Solo, Chewbacca, and Leia. Although C-3PO is not completely assembled in the scene, he is definitely visible to Vader.
R2 doesn't know it. It's as simple as that. He isn't present on Mustafar (he flies with Anakin but is ordered to stay at the ship. He isn't present while the slaughtering of the seperatists or the fight of Anakin/Obi-Wan.), differently to Obi-Wan and C-3PO.
The two droids were dumped back on the streets, their memories wiped of the incident. Unlike R2-D2, Threepio's mind is wiped of all memories after the birth of Luke and Leia.
Vader agreed to help the handmaiden, silently recalling the time he spent with Padmé in the process. In this moment, he was once again Anakin Skywalker, a young man in love who simply wanted to change the world for the better.
You'll remember that, in the conclusion of Revenge of the Sith, C-3PO's memory is wiped, so he loses his knowledge of the past. R2's isn't stated to be erased, so he presumably maintains his memories; why does he never tell Luke about Anakin? Well, maybe he didn't want to.
Landing on Tatooine, the droids were captured by Jawas and sold to Owen Lars, a moisture farmer; Lars charged his nephew, Luke Skywalker, with care of the droids -- but Artoo proved difficult to control. He left the homestead on his own, claiming he was on a mission to deliver a message to Obi-Wan Kenobi.
In The Phantom Menace, set 32 years before A New Hope, R2-D2 is portrayed as belonging to the Naboo defense forces, one of three astromech droids deployed for repair duty onboard Queen Padmé Amidala's (Natalie Portman) starship as it attempts to get past the Trade Federation blockade.
Now, the R2-D2 card wasn't particularly powerful, and it certainly did not say that he was "Force-Attuned" or "Force-Sensitive." However, in the game, when R2 was present at a scomp-link (one of those little terminals he plugs into all the time) he could effect the Force reserve of the player.