The operation succeeded but the patient died

[Dr Jekyll]

What's your profession's equivalent?

I'll start with 'The project was successful but the business didn't benefit as we'd expected.'

[vaud]

Mine was telling my boss that we secured a huge sale of kit that scanned and OCRd audit/financial records.

To Enron. A month before they collapsed. And no the deal didn't go through.

[vulture1]

At my work I was in charge of the fresh area (large supermarket)
The chillers had never had a proper clean organised by any manager as they always failed to plan it so when the yearly night eaners came in the shelfs got a bit of a clean and that was it. As opposed to a strip everything off take off the bottom shelfs suck out all the crap from below and the ducts etc.
This is needed to stop chiller breakdowns.

Upon making this actually happen on a nightshift over 3 weeks amd a huge team to do it almost every chiller broke down within 2-3 weeks afterwards...

[Truckosaurus]

I've worked on several IT projects that were completed but didn't get to go live - most recently some Brexit related ones to cover various Deal/No Deal scenarios that might have occurred.

One, many years ago, was canned midway but the customer decided it was cheaper to complete the development and test phases that had been 'paid for' rather than down tools and renegotiate the contracts. (That was a public sector customer if you couldn't tell).