Early in my career I found myself in a situation, as a new IT manager for a company that had already hired a consulting company to begin design of their first system. The mess was not even created yet, but I could see a large issue with a major design decision that I pretty much knew would not work.
This being a number of years ago, systems were only beginning to be though of as anything close to real-time, and there was still a lot of batch-processing going on. The company was a wholesale food distributor shipping daily numerous truck loads of custom-picked grocery orders. Since businesses and institutions ordered supplies for immediate needs, if an item was out of stock it was customary to substitute a similar product so they would have something to use. The consulting company had convinced the owners that they could batch-process three-part invoice documents for all the orders and pass these to the warehouse crews to be processed. If there were out-of-stock or product substitutions made for an order, the invoice would be returned to IT to be corrected and re-printed while loaded vehicles and drivers waited for corrected documents to be delivered with the orders.
I sat down with my supervisor, one of the owners, and explained the design flaw and described the delays these corrections would create. His response was 'We hired these consultants to do the design and we will do it the way they advise, and your job is to make it happen.' I responded that I was willing to proceed on the basis that he had been made aware of the problem and had instructed us to go ahead.
It was only a couple weeks into the gradual implementation of the new order processing system when my supervisor walked into my office and asked how much effort and how long it would take to change the process to one of providing simple order-picking documents, then return these to IT for corrections and substitutions before printing completed batches of invoices.
So, the first thing you need to do with a mess is to make its existence known to the proper people, adequately describe the real or potential problem, explain the options, and get decisions made at the highest possible level of responsibility. Don't wait until critical systems fail and cause what can be major disruptions to business. And of course, if warranted, remove yourself from the situation before the crisis point is reached.
The only thing worse than being an influencer
is believing one.