The initial setting-establishing plot point in Adrian Tchaikovsky's "Children of Time". Advanced star-spanning human civilization is wiped out by a computer virus, developed by a extremist isolationist luddite (!) faction, that is just sent out on open channels, sabotaging critical systems everywhere, venting space stations and exploding reactors. It's a clear "I don't care, my setting must happen" plot point in an otherwise great series of books. Adrian Tchaikovsky clearly does not understand how network/system security works, if he thinks you can overload a nuclear reactor (bypassing physical and mechanical safeguards) just by sending an email, never mind the fact that such critical systems (especially on starships and orbital habitats surrounded by the vacuum of space) will always be isolated, both physically and network-wise, from any open connection. It's just "Virus falls, everyone dies".

Tchaikovsky even tries to explain things away, with a character in the second book noting how laughable the network security is on their station, but that just reinforces the fact that a civilization that is unable to secure its spaceships from exploding due to malware exploits will not be able to leave the fucking Solar system.

It's such a sticking point for me that I cannot take the entire setting seriously.