This story has been told many times and this account is not the most complete. Pixar did recover the data from a home office setup and complete the movie, but

This story has been told many times and this account is not the most complete. Pixar did recover the data from a home office setup and complete the movie, but Pixar is so perfectionist about story-telling that the creative heads decided the end result wasn't good enough. The story was rewritten and the movie changed so much that almost none of the recovered data was in the version that was finally released.