Pixar's first feature film was Toy Story, released in 1995. The movie was distributed by Walt Disney Pictures, eleven years before they bought Pixar. It was a somewhat hesitant collaboration, and it seems truly weird 27 years later that Disney did not have much faith in Toy Story. And neither did their usual merchandise vendors. You would think that a movie about toys would have plenty of toys available for kids by Christmas, but thousands of children who had asked Santa Claus for a Buzz Lightyear doll were disappointed when the only manufacturer willing to make toys for Disney couldn't fill the demand. Disney lost millions in potential toy sales because the upper echelon suits thought Toy Story would be a flop.
Of course, Disney came out okay in the long run, as they always do. They bought the Pixar company in 2006, and now have three sequels and a prequel to Toy Story. But why did they think Toy Story would be a flop in 1995? The merchandizing mistake is explained in detail at Slashfilm.