This is getting out of control. I have a project. 19 tracks on it so far.
When i duplicate a track or add a new instrument i get no sound. The instrument detects midi but i get NO SOUND!
Tracks that are already there work fine. Even when i leave the track, save and open again i still get no sound 
I got multiple instances of diva, tal uno lx, and kontakt. All the same.
Cubase 6.5.4 x64, Windows 7 x64
Please help thanks
If the track is selected, and you are playing on the MIDI keyboard, can you see incoming MIDI data (monitor switch has to be switched On, of course)?
Are you using 32/64-bit Cubase?
Can you try to increase the Buffer Size?
Are you using Instrument tracks, or multi-timbral VST Instrument window?
Yes i can see incoming midi data… cubase 64 bit. Instrument tracks
Is the same problem with only one project? Or can you try to simulate this in different project?
Can you try to Backup this project?
it’s only with one project
Honestly can someone help me! I spent $500 on this program and I’m getting no help! This is so frustrating
It’s only happening with one project. And now if i add a new instrument track i get no sound!!! CMON someone help
this only happens with instrument plugins that are already being used. Im using multiple instances of diva, kontakt, and tal uno lx. If i try to add another of them, no sound.
But let’s say i add rob papen predator, which i haven’t used yet, it works fine. And when i duplicate it it works also
Did you try to backup it, and open the backup? It often helps in these cases.
just tried, didn’t work
cant you just export / render / save settings from all your tracks and build a second new project from the faulty one? And for each step try out if this step makes the project faulty. and if everything works in the end… then its good…
how do i do that?
just recreate / copy a new project from scratch. and watch the new project closely if it gets the same errors.
export audio parts save vsti / effect / channel settings temporarely… etc export midi…
just take the clean data and put it into a new clean project.
I had once a WAV file (must be corrupted or something) that crashed Cubase - it was 100% reproducable. When I found out it was this file. I deleted it from the project and all was good afterwards.
Calm down. Check the outputs of the tracks that won’t give you
acoustic feedback. Is the instrument loaded correctly? Is there already a preset chosen?
Do you use shareware plugins (check the plugins user interface if there’s a counter in
it that you have to close; this often appears in shareware plugins with the request to donate)?
Can you open up a new instrument track with Halion Sonic SE and check if it works please?
And don’t be so impatient. We’re just users helping users. Not the tech support.
There’s an easier way. When you just use instrument tracks, create
Midi Loops from the ones thak work and open them in the new project.
Backup: menu > File > Back Up Project
Make new folder, and click OK. 
Yeah, that’s how its done usually.
But he already said that it did not work.
Which I understand as he tried but the new project
caused by the backup gives him the same creeps.
Set Locators > Export > Export as Midi Loops > Set Rules
You can save the VSTi and the loaded sound with the Midi Loop.
Then import it via the Media Bay and there will be an instrument track
created with the VSTi loaded and your Midi Events on it.