My result here was that running the 'Vienna Ensemble PRO 5 / MIR PRO / MIR PRO 24 (Mac OS X) build 10988' installer made the Vienna Ensemble Pro folder in Applications vanish altogether, complete deletion of the application. and nothing in the trash.
OSX.6.8; the extant installation was 5.0.10683. Is 10738 a prerequisite or is this just botched. and the new VI Pro installer got rid of the VI Pro AU, so there is nothing in VE Pro where that is instantiated. I don't think it's me, unless both files were strangely corrupted. they were the right size and there was no indication during the installation of any problem.
I had no problem reinstalling 10683. or the prev. version of VI Pro archived.