How to figure out which parts you are missing to use a craft file?

[Galane]

Some of my old rockets won't load due to "locked or invalid" parts. I'm missing a mod, but which one?

It would be nice if KSP would have a popup on those ships listing which parts it cannot find.

Looks like a job for a plugin to audit craft files for missing parts.

[Justin Kerbice]

By using KSP mod admin for example, which highlight these parts in red.

[Galane]

Nice program. Just the old version of Infernal Robotics, and they are all experimental and testing crafts I can delete.