[PvK]

If you're playing using Proportions Mod 2.x (?), and have upgraded your game from an earlier Version of Proportions Mod, some components may not be repairable, so you'd need to refit to a design that uses current components.

Also, even in unmodded, there are a few component types which intentionally can't be repaired with a mere repair component - they require a full shipyard. They are the emergency components and stellar manipulations, mainly.

PvK