I am in 3rd line support. We do a lot of bug fixing (although we should be doing other stuff). Quite often, we get systems which are so badly designed and configured (at the server OS level and software level) that they are beyond repair.

Yet my manager, even though he was a dev, may swear when I tell him the system is unrepairable (As the person who does our server work gives an opinion that it's FUBAR). However, he still expects it to work without a rebuild. How can I make it work like that when a guy with a million years more experience says the system needs a rebuild?