There are several different ways to answer when you're asked during a job interview what your greatest weakness is. You can mention skills that aren't critical for the job, skills you have improved on, or turn a negative into a positive.
Even though the question is about weaknesses, your answer should always be framed around positive aspects of your skills and abilities as an employee.
Discuss Non-Essential Skills
One approach to answering this question is to analyze the key skills and strengths required for the position you are interviewing for and then come up with an honest shortcoming which is not essential