To have a "complete" save file through the Kanto arc, you must follow these specific anime-based events: The Rare Pokémon

By following this guide, you will never lose your progress in the Kanto anime adventure again. Now go—and become a Pokémon Master, even if you take a shortcut to get there.

This is the most critical section. A save file ( .sav or .sa1 ) is universal. If you download a random save file online, it will likely crash or show “The save file is corrupted.”