I think there was an unmanned Ariane 5 space rocket carrying four satellites that was lost on launch due to a software integer problem. They used older software from Ariane 4 and it ran out of numbers when Ariane 5's flightpath was different. It's quoted as the most expensive software bug in history.
I think the Mars Climate Orbiter ended up costing a fair bit more overall....
https://sma.nasa.gov/docs/default-so...vrsn=eaa1ef8_4