Seminal papers that later were proven to contain errors I was reading on institutions, and I came across Acemoglu, Johnson and Robinson (AJR) paper on The Colonial Origins of comparative development: An Empirical Investigation, and this paper seemed so 'perfect' that spawned a lot of other papers based on the data of ancient settler mortality rate and how it was used by AJR as an IV for the current quality of Institutions in former colonies. 

However, as I began searching more on this paper, I found out that the paper is in fact ridden with errors, specially on data treatment. (Albouy's 2012 comment on the same paper, published by The American Economic Review)

I would like to know, if, besides this paper on development economics, are there any other seminal papers, in any area of economics, that later on were proven to have crucial mistakes/errors that invalidated the paper conclusions?
My favorite example is the initial formulation of Arrow's impossibility theorem in the first edition of Arrows' "Social Choice and Individual Values" (1951). In the first edition, Arrow claimed that, together with 4 other conditions, the following domain condition


  ``The domain $\mathcal{D}$ is sufficiently extensive so that there exists at least one free triple of
  alternatives. (A triple is called free if all conceivable
  combinations of individual orderings of this triple actually occur in
  $\mathcal{D}$" (rewording from Blau(1957))


implied that there exists no social welfare function $S : \mathcal{D} \rightarrow \mathcal{R}$, where $\mathcal{R}$ is the set of all possible orderings (i.e. complete and transitive binary relations) over the set of alternatives $A$.

This was later showed to be false by Blau (1957) The Existence of Social Welfare Functions" Econometrica Vol. 25, No. 2 (Apr., 1957), pp. 302-313 who provided a counter-example. 

Blau also showed (among other things) that the theorem could be corrected by replacing the above domain condition by the following condition


  Universal domain : the domain $\mathcal{D}$ of the social welfare function contains every possible profile of preferences over the set
  of alternatives $A$ (with $|A| \geq 3$).


Arrow later corrected this mistake in the second edition of Social Choice and Individual Values (1963), and the formulation of Arrow's theorem using the Universal domain condition has now become standard.

This being said, the initial error in the first edition of Arrow's book was rather minor, and the solution proposed by Blau does not reduce in any strong sense the importance of Arrow's result and approach. Intuitively, the conclusion remains that on a vast domain of relevant economic problems, no social welfare function satisfies a set of rather basic and reasonable conditions. 

So this might not be exactly the kind of errors you were looking for (definitely a seminal paper though!), but I like the example so much I could not resist posting it . If such brilliant people like Arrow make these kind of mistakes, I guess it takes a little bit of the pressure off for everyone else?