[ New note...addendum] After posting this, I went back into the render dialogue and thoroughly checked and unchecked all option settings, individually and multiple; and when I was done, I could choose the mp3 quality setting I wanted AND could continue with an active "Render" button. So, SOLVED, by randomly clicking on everything in turn... [my original whine follows...]

Greetings,

I have recently purchased and installed Vegas Pro 18 (build 434) and have not been able to render multitrack audio files to mp3.

In the "Render As" dialogue screen, I am able to select MP3 as an option, and choose the quality, but no matter how I've fiddled with various settings the "Render" button stays inactive.

On the "Components" tab under the "About" menu item, there seems to be indication that an mp3 plug-in is installed:

    mp3plug2.dll
      version: 3.0.0.14
      path: C:\Program Files\VEGAS\VEGAS Pro 18.0\FileIO Plug-Ins\mp3plug2\mp3plug2.dll

I have for years been able to mix 5 tracks of audio wav files in Vegas 9 and render as an mp3. I pursued an upgrade for some of the video editing features, and will be sorry if I cannot get to use the new program for my audio editing also.

I do have Sound Forge installed, but I vastly prefer working in the Vegas environment, with which I am much more familiar.

Several video editing projects have run smoothly on my Intel Core i7-6700K CPU 4GHz w/ 16 GB ram in this 64-bit Vegas Pro 18.

Any suggestions of how to activate / revive / engage the ability to render audio as MP3 would be appreciated.