You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
FC_Barcelona

Context:
In late December, Barcelona's appeal to the Court of Arbitration for Sport was unsuccessful and the original transfer ban was reinstated, leaving the club unable to utilise the 2015 winter and summer transfer windows. On 5 January 2015, Zubizareta was sacked by the board after 4 years as director of football. The next month, Barcelona announced the formation of a new Football Area Technical Commission, made up of vice-president Jordi Mestre, board member Javier Bordas, Carles Rexach and Ariedo Braida.

Question:
During what year was Barcelona not allowed to use  their transfer windows?

2015