"I'm placing these droids in your care. Treat them well. Clean them up. Have the protocol droid's mind wiped."--Bail Organa, Star Wars Episode III
"Our last master was Captain Antilles,"--C-3PO, Star Wars Episode IV.
Since my Star Wars: Edge of the Empire game has delved into a lot of conspiracy theories lately, the old wheels in my head started turning. Why not look at what kind of crazy things really happened between the frames of the movies?
In this vein, I thought I'd kick off this round of conjecture examining one of the greatest mysteries an all of the Star Wars galaxy. What's that? The secret of C-3PO's mind wipe!
We know that droids develop stronger personalities the longer they go without a mind wipe. We know that C-3PO has almost the same personality in the prequel trilogy as he does in the classic trilogy. While it's possible he just happened to develop the same personality based on his experiences from the end of Episode III on . . . what if the answer isn't just coincidence?
First off, why was C-3PO mind wiped and not R2-D2? That's easy to answer. R2-D2 was in military service. R2 units were regularly mind wiped after missions. Even if it wasn't obvious enough to determine from context, the Clone Wars series clearly establishes that Anakin flaunts the usual military protocols when it comes to mind wiping R2-D2. But as far as Bail Organa and the crew of the Tantive IV are concerned, R2 has been getting his regular mind wipes and doesn't need to be scrubbed.
Of course, that means R2 spent the next 19 years or so making sure that he didn't get mind wiped again, but hey, he's resourceful . . . as we are about to see as this conspiracy unfolds.
Protocol droids don't get a mind wipe on a regular basis, because part of their job is to know appointments, contacts, and important dates relevant to their master. For maximum safety, Bail had to make sure that C-3PO couldn't give away details about Luke, Leia, Obi-Wan, or Yoda, even if he didn't know much.
Now, R2-D2 has grown fond of his fussy friend. He knows that a mind wipe is imminent. While he could just create a backup of C-3PO's memories and restore his personality, R2 also knows that C-3PO is almost a Jar Jar Binks level security threat if allowed to keep too many sensitive details in his databanks.
R2-D2 needs to have a significant length of time for C-3PO to exhibit his personality in his memories to "lock in" who he is. But none of 3PO's memories are safe to leave with him. This causes R2 to formulate a plan. C-3PO needs safe memories to "live" in. So R2 starts to comb holonovels and documentaries for stories of two droids aiding a group of humans. Once he has assembled years and years worth of data, he programs C-3PO with these false memories.
R2 realizes that 3PO's memories might sound familiar to people that question him, so R2 places a sub-routine in 3PO's mind that will cause him to replace details of his memories as he encounters things in the future. So a planet in a holonovel will be replaced with a planet where the Tantive IV has visited, and a former owner that was an archaeologist in a documentary will be replaced with a prominent professor that C-3PO has personally met.
Once all of that has been set up, R2 backs up only the segment of C-3PO's memories from the implanted section of his databanks, and has them ready to reinsert into his mind once the memory wipe has been performed. When Bail order's C-3PO's memory wipe, R2 isn't laughing at his compatriot's misfortune, he's laughing because his master plan is all falling into place.
R2's customized memory sub-routine is the reason the C-3PO remembers starships that hadn't been produced yet, encounters with Boba Fett, and a host of multiple masters before Captain Antillies of the Tantive IV.
And who knows how many times, while 3PO is chastising him, R2-D2 regrets saving his friend's personality.