I have bought a new MX400 and connected via USB.
The MX400 is shown by the MIDI-devices  (and marked)
Cakewalk does also prompt when the MX400 is powered on and off.
But the vst-plugin says that there is no device.
 (With the MX-Edit I can communicate withe the MX400.)
  
I read that maybe a problem with 64-Bit Windows.
Is anyone running a MX400 with Windows 64-bit and SONAR in 64-bit?
 
 

I sold my MX400 and happily bought software to replace it, like Valhalla Room, Breverb, etc.  In my case, that has worked out better for my workflow since I wanted to be able to use these tools all over the place and not be limited to just a couple inserts etc.  Much more flexible for recording purposes anyway.

Have you tried rescanning your plugins?

Yes, I rescanned the plugins.
I can load the plugins (MX400 Dual Stereo A and B) as well.
But then I get the message from the plugin "No available devices was found".
I read an article that the plugins are very poor and have problems. And I found a post in this forum that someone had the same Problem within Sonar.
I would like to know if the problem is with me or at the Lexicon plugin.

I have a Lecixon MX200 but I use it as a regular outboard reverb device.  I've never used it via USB not evern once.  Since there are so many VST reverb plugins, you really don't need it.  I connect mine for vocal monitoring so the vocalist can hear reverb in their headphone when they sing.
 
Peace..

I just found an old SOS article about the Lexicon MX400 which reminded me my I use my MX 200 strictly as an outboard reverb.  The Lexicon MX units do not allow audio to pass through the reverb using USB.   USB is only for controlling the MX edit software on the computer, the reverb unit must still be connected via the audio cables.
http://www.soundonsound.com/sos/nov06/articles/lexicon.htm
 
I hope this helps,
 
Peace.

Thank you.
I know that the plugin is only for controlling the output device.
And I know that audio does no go through the lexicon usb.
But I wanted to conrol the lexicon and save the presets within sonar.
Too bad that even that does not work.
 
 

I am having a similar problem with my MX300 - but I think it has to do with the warnings that you will get this error message if SONAR (or any DAW) grabs the MIDI port of the MX unit. My MX shows up in the preferences/setup section of SONAR, and its audio and midi are de-selected, but it still cannot load the VST properly. So I assume it is some snafu to do with SONAR and your interface (mine's a Focusrite Scarlett 18i6) and SONAR grabbing up all those resources when it loads.
 
However, we do use Windows. And I can run MX-Edit in its own window, outside of SONAR, and control the MX that way - it still passes audio to and from my interface (and therefore SONAR) via the S/PDIF connections just fine - all the while being edited from MX-Edit outside of SONAR's shell. Yes, being able to bring up the edit window through the VST interface would be AWESOME, but everything on my MX works fine other than that and having an outboard reverb/delay box is awesome. It takes no CPU cycles at all and is super smooth in real time.
 
All I can say to you is to make sure you have all the proper (read: updated) drivers for you MX installed. Mine came with drivers and software for Windows XP - I had to find, download and install different drivers for Win7/64bit. Aside from the VST not properly loading the MX-Edit app (which admittedly installed and reports as a 32bit VST), it should otherwise work just fine.

Update: I have gotten the MX300 to successfully load as an F/X in the F/X bin of a track. Of course, you need to be using S/PDIF for the actual hardware audio in/out between your interface and the effects unit, but getting its VST/app to run as a plug-in makes changing patches and editing patches a whole lot easier than using MX-Edit outside the SONAR shell.
 
The secret to getting it to work, as best as I can tell (and reproduce) is that I do not plug my MX300 into the USB port until *after* SONAR (X2 Producer) has fully loaded. If the MX is already plugged in when SONAR loads, you will get the error screen (cannot find device or device in use). Wait until it has loaded, plug in the MX's USB cable and let it be discovered, then you will be prompted to install/use the MX by SONAR, and it will then be available for use as a plug-in.
 
Trying to attach a pic as proof here:
 

 

Here is a link to documentation from Lexicon for this device:
 
http://www.lexiconpro.com/en-US/products/mx400
 
In it, they quite clearly indicate that it is 32-bit only, so whatever it loads will get the BitBridge (or JBridge if you own that) treatment.  Many 32-bit plugins do not seem to play well in 64-bit Sonar, but it varies widely as to which ones do or do not.
 
If you have a 32-bit Sonar installed, you could try launching THAT, and then see if the Lexicon loads up properly there, as it would all be native 32-bit.
 
As far as seeing it in Sonar, you would have to make sure the path to it is in your search path for VST plugins.  You might also have to check the box for the setting in Preferences that tells Sonar to Open All Devices (or whatever the exact wording is).
 
The 'Always Open All Devices' setting is actually in: Preferences>Audio>Playback and Recording.
 
I hope any of the above helps, 
 
Bob Bone