I get this message when trying to load any sound to LPX from the library..... it's like the link to the content has gone missing.... I did have to reinstall the OS a few days ago... I tried to manually refresh content, but nothing. The patch is from an older version of MainStage. Open the patch in MainStage 3 or later, export it again, then open it in Logic Pro. OK... but surely that doesn't mean "every" patch?