OK, I suspect this is being caused by a Musiclab VSTi, RealLPC, which is a guitar emulation VST (and a damn good one at that). I’m using the 64 bit dll in 64 bit C6 and 64 bit C5, but the 32 bit dll in C5 32 bit. As mentioned, 32 bit C5 is mixdown OK. Therefore, it’s the 64 bit dll of the VSTi since the problem doesn’t exist in 32 bit C5. This is very likely to be the case as Musiclab just released the 64 bit version very recently…like maybe last week…and I did the update. I shut it off in the project and everything else went through as normal.
I’ll contact Musiclab with the probable bug. I haven’t tried it, but I suspect this will be the same for their other recently native 64 bit VSTi’s: RealGuitar and RealStrat. In the meantime, if this fits your situation as far as use of the Musiclab VSTi’s, try using the 32 bit version through the VST Bridge or just using 32 bit Cubase for mixdown.
BTW: For those guitar players out there shaking your heads - Yes, I do play guitar. But I’m a better keyboard player so it’s quicker to use these top-notch emulator programs when I’m doing music for production music libraries. I haven’t had a publisher refuse a single tune based on emulations yet. Now, that should void any possible flames on this thread, thank you.