This is the correct answer, IMHO. The OP isn't in a position to stop a coworker from holding the company hostage. But the manager certainly could, despite protestations of "there is nothing he can do about Mr. A". That's just nonsense.

@JoeStrazzere But the manager certainly could, despite protestations of "there is nothing he can do about Mr. A". It's not necessarily nonsense, if the manager's manager is the one who refuses to do something about it. The buck stops somewhere, but not necessarily at the first level of management.

@MauganRa: That is what I meant by "The buck stops somewhere". I was merely countering the implied assertion that management (as a whole) is able to do something about it. Being told to not touch Mr A's employment could effectively run all the way up to a stakeholder or board member, which absolves the management from having mismanaged the situation.

I disagree with this answer. You have told OP what they SHOULD do in their current situation, not what they CAN do to fix the situation if for some reason they feel like it's up to them to do so. There is never nothing someone can do about a situation. As stated in gnasher's answer, there are courses of action that OP could suggest to his superiors (who it sounds like are equally as tired of Mr A as OP is).

@Korthalion gnashers advises the OP (not the manager) to hire some developers (out of his own pocket I guess). Give them company property and knowledge etc,... best case scenario is OP gets fired for stealing code for outsiders... or they end up in jail

It's amazing how many idealistic answers are here that would get OP canned by the end of the meeting. This is a company culture thing and the way to directly influence company culture is to be high up in the company.

Upvoted. Having been in this exact situation, and having tried everything I could think of to bring the company to a place of modernity software wise, I found the best personal recourse was to quit. ymmv!

@Kilisi: "Out of your own pocket" is obviously nonsense.

@gnasher729 no offence, but your whole answer is for the OP to do something he/she cannot actually do... the boss could do it... but not a new hire who is just a colleague and a junior one at that... Hopefully the OP doesn't follow your advice or they'd probably be unemployed soon At best you're advocating that a new hire pressures his bosses to fire a senior and outlines a devious strategy to do so (after the boss has already indicated that nothing will be done)... that is unlikely to end well either.

@Kilisi "As stated in gnasher's answer, there are courses of action that OP could suggest to his superiors (who it sounds like are equally as tired of Mr A as OP is)."

@Korthalion it doesn't say anything about suggesting to superiors, but I'm not going to discuss someone elses answer further, feel free to downvote and move along

Your answer is indeed the correct answer in most cases. However, I'd not downplay what a determined developer can do with some complicity from management. The key point here is that management already tried to fire the guy (unsuccessfully), so they probably know Mr A writes terrible/unmaintainable code. In my current company we faced a very similar problem (but the dev in question was just old and ignorant, not actively problematic), and we solved it by slowly refactoring everything into more manageable code. It's still not perfect, but nothing caught fire when that dev finally left.

@Korthalion Given that the management already fired Mr. A once and brought him back, and the manager has already told the OP that nothing can be done about Mr. A, how is a new hire going to "suggest" to the manager that they should deal with the "Mr. A problem"?

@MaskedMan probably during his exit interview or PIP meeting

the code that is making the money is always the most horrible code. it's always having to answer to actual customers. because of this, it thrashes around, and corners get cut on ideal practices. it's these horrible code-bases that provide the funding for the nice ones that make incoming software engineers happy. every time i see one of these stackoverflow posts of a new employee coming in and complaining like this, there is always a sense that the people that created the system that brings in money are idiots; and the new guys are smarter though they don't have a cash cow application.