Star Wars revealed that Yoda received a warning about Order 66 at the start of the Clone Wars, making it unclear why the Jedi Master chose to ignore it. Order 66 wiped out most of the Jedi Order, so if Yoda knew about it in advance, then he could have taken steps to make sure it didn't happen.
So, it's likely Yoda didn't want to interfere and alter the future, as he'd be at risk of preventing the Sith from being defeated many years later. While Yoda sensed that the Sith's plan involved the Clones, it was too late to prevent Order 66.
However, most specifically, Yoda could have prevented Order 66 if he'd paid closer attention to his own Force visions. In the Star Wars short story anthology The Clone Wars: Stories of Light and Dark, Yoda has a vision of dark happenings surrounding the clone troopers.
As seen in Star Wars: Episode III - Revenge of the Sith, Yoda was on Kashyyyk helping the native Wookiees fight off the Separatists when Order 66 was issued.
History. Sifo-Dyas was the only Jedi to know of the chips' existence.
Ultimately, Yoda gained a new understanding of true selflessness and of the Force, came to realize his hubris and the mistake the Jedi Order committed by becoming warriors, and unlocked the secret of Force immortality. As the Clone Wars raged on, Anakin and Obi-Wan had become heroes of the Republic.
He was still completely unaware of the Sidious/ Palpatine connection until ROTS. He also said during TCW season 6 that the Jedi order must believe in the clones and end the war before the Sith's plans are realized.
All season, The Bad Batch has been showing the pangs of regret that some clones feel over actions such as Order 66 and the destruction on Kamino.
In Legends, the Jedi knew about Order 66. They just didn't know it could be used in the way it was. It was billed to be used for taking down dark Jedi or rogues. Even before the biochip thing, the clones were flash trained with the expanded meaning of the order, which the Jedi were unaware of.
Rise of the Galactic Empire
Bode used his skills as a spy that he learnt working for Republic Intelligence to evade the Jedi Purge when Darth Sidious executed Order 66 and reorganized the Republic into the Galactic Empire.
Without Order 66, Palpatine would definitely lose. If Order 66 happened but not for some of the most powerful Jedi and the more battle-hardened and experienced Clones, Palpatine still loses even though many Jedi are killed.
Yoda didn't specifically know how this would go down, or to what degree Anakin would cause it to happen, but he was playing a much longer game by Revenge of the Sith, and that's at least, in part, explained by Yoda's Force connection with Qui-Gon's spirit.
In The Mandalorian Season 3 Episode 4, we finally learned who saved Grogu from the Jedi Temple during Order 66. None other than Jedi Master Kelleran Beq, The Sabered Hand. But who is Master Beq and why is his appearance in The Mandalorian so important?
Presumably Palpatine planned to have Anakin join him at that point and so told the clones not to kill him when he gave out Order 66.
Master Yoda failed Anakin Skywalker in Star Wars: Episode II — Attack of the Clones, and it resulted in the destruction of the Jedi Order. Master Yoda is one of the most revered characters in the Star Wars universe, and for good reason, but he ultimately failed in stopping the rise of the Sith.
Yoda was reluctant to train Anakin in Episode II because he said Anakin was too old to start training (even though Anakin was still a boy). However, in Episode V, Yoda didn't seem very reluctant to train Luke despite the fact that Luke was a full grown man by that time.
Unsure what to do and feeling he could never be forgiven for what he had done, as well as desperate to save his wife, Padmé Amidala, from the possibility of a presaged demise, Skywalker betrayed the Jedi and and was "knighted" by Sidious as his new apprentice, Darth Vader, Lord of the Sith.
Jedi including Oppo Rancisis, Coleman Kcaj and Kirak Infil'a are mentioned on the Inquisitorius' list of surviving Jedi after Order 66. Other Jedi like Master Uvell and former Padawan Gungi have been confirmed as survivors.
But these complaints often ignore the sheer number of Jedi who did die during Order 66 and shortly afterward. We are talking about, at least, a few thousand. Considering how few survivors there are—less than 100 as of 2023—the actual death toll is probably closer to nine thousand or so. That's still a lot of dead Jedi!
Order 67 was an order requiring clone troopers to dance. During the Battle of Utapau, Darth Sidious accidentally issued Order 67 when he meant to use Order 66. Just after the order was executed, Cody and his troops began dancing. However, Sidious browsed a manual and executed Order 66.
Despite Cody's friendship with Obi-Wan, he didn't hesitate when he received Order 66 from Supreme Chancellor Palpatine at the end of the Clone Wars. Obeying the Republic's commander-in-chief, Cody gave the order to fire on his Jedi General, then sent troops to see if he'd been killed.
Other Clone squadrons, such as Omega Squad, Delta Squad and Ordo Skirata, disobeyed the order as well, but feigned compliance to avoid suspicion from the Empire.
Palpatine admits to Darth Vader that the Jedi he actually feared most was none other than Jocasta Nu.
Why Qui-Gon Jinn Was Palpatine's Greatest Threat. Unlike Yoda and the Jedi High Council, Qui-Gon Jinn was only concerned about the will of the Force. Therefore, Palpatine needed Qui-Gonn out of the way because he was better connected to the Force than the other Jedi.
Return of the Jedi establishes that Yoda was aware that Anakin Skywalker had fallen to the dark side and become Darth Vader. When questioned by Luke Skywalker, he confided that Anakin was Darth Vader. Later, Obi-Wan Kenobi's Force ghost confirmed that Anakin had indeed fallen to the dark side and become Darth Vader.