☛ This type of question, especially if the phrasing is a bit more like the second example, puts you automatically on thin ice. Most people, even if they don't consciously think about it, don't want to hear someone bashing an old boss, fellow employee, etc. So, this question must be handled with tact and graciousness. Focus on your actions and focus on what you did to try and make the situation better. This is similar to discuss performance/training related issues and what you did to help not just "train" but also train to eliminate the cause of the problem.

☛ This is also a personality check. Besides not wanting to work with a person who blames others or bad mouths, businesses thrive when problems are solved, when initiative is taken, when someone steps up. Even if the solution isn't elegant or as soon as you finish something it becomes useless, outdated, or the like, it's at minimum an effort as seen by any employer and a learning opportunity for you.

☛ Also, going back to that earlier comment about no one being an island unto themselves, this is also a barometer on how you function as part of a team - and here you can knowingly or unknowingly give away your strengths and weaknesses.