Frustrating....
I'll tell you what i did and in what order, for what it's worth...
Downloaded and installed LCC 5.4.18.6-Restarted computer.
Uninstalled VI & VE, Reinstalled Latest VI..(Not VE as i don't use it at the moment..)
Opened Directory manager, dragged and dropped instruments, reset custom folder...
Repaired permissions in disk utility-twice!-restarted machine...
Opened VI standalone, loaded an instrument, all worked fine, closed app.
Openend Logic 9, in Preferences/Audio units manager reset & rescan vienna instruments.
Opened an empty Logic song, loaded 1 VI instrument-this is where i expected prob but all was fine.After this point older projects with VI worked as desired.
Maybe the sequence is important?-I say this because the chain of events was suggested elsewhere in this forum(by Maya?) and seemed to suggest some success.It worked for me this time on a mac pro, as it had done previously on a Quad with earlier Logic and VI builds.
I find a lot of computer problems and solutions as baffling as homeopathy, but i have developed some conditioned responses , like a dog who lives near an electric fence...
Energy saving preferences seem to have an adverse effect-If the machine goes to sleep, or drives spin down from inactivity it inevitably causes problems.
Opening other apps while a project with VI is loading and particularily, going online during a loadup seems to cause bad stuff.In fact i think this may have triggered my most recent problem....
Best of luck...
Ray