Pokemon-go – Selected Pokémon has not been obtained in this save file & cannot be withdrawn

pokemon-gopokemon-homepokemon-sword-shield

After having transferred a Mew and a Mewtwo to Pokémon Home from Pokemon Go, I tried then transferring them to my Sword boxes:

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But I got the error message:

The selected Pokémon brought over from Pokémon GO has not been obtained in this save file.

The Pokémon cannot be withdrawn.

It clearly isn't all Pokémon that are locked to first being obtained in a certain save file. Mewtwo can be found in the Dynamax Adventures, so okay sure whatever. But Mew isn't obtainable unless you buy a Pokéball Plus. Obviously, I could also do a quick touch-back trade with someone who has a Mew and quickly unlock my own for game use, but what is this point to these locks?

Which Pokémon are locked for the whole GO —> Home —> SWSH process? Is there a good reason for it?

Best Answer

The website for Pokemon Home has an info page on How to receive Pokemon with this brief answer:

Conditions for withdrawing Pokémon

In order to bring certain Pokémon caught in Pokémon GO and transferred to Pokémon HOME into the Pokémon Sword or Pokémon Shield game, you must either have registered that Pokémon’s species to your Pokédex or have obtained a Pokémon of that species at any point in that game. A list of applicable Pokémon can be found by going to the Help menu in the mobile device version of Pokémon HOME and selecting Other.

Incorporating Dave's comment, that list contains basically all the legendary and mythical pokemon.