I have found that for some unknown reason, multiple instances of the stabilizer problem is created. When you look at a clip's effect window, you will see multiple instances of the stabilizer plugin which results in a very unstable image. I don't know what causes this, but before I render a sequence I have gotten into the habit of checking and I find that I have to close all but the original instance of the plugin. This might be the cause of the problem you are experiencing.

What resolution and frame rate are the clips? 11 has a "bug" in which is fails to render 60fps clips correctly. 23.97 clips seem to do ok.

I have actually moved back to Vegas 10 for the time being. It stinks but atleast stabilization isn't crippled. The way it was implemented in 11 just plain stinks.

Probably my fault, but I never liked any of the built-in stabilizers - mostly because they zoom rather much - so I'm still deshaking everything from handheld video to downhill skiing with the "New Deshaker" see http://www.guthspot.se/video/deshaker.htm and search for it in this forum.

As it can deliver the deshaked result in any Vegas rendering template you might even get it in a form where Vegas can smart-render it - and so you can avoid losing too much video quality.

I've found that I get the best stabilization when when following this principle:

When stabilizing video in Sony Vegas 11 using the internal stabilizer or Mercalli V2, best results are obtained when matching properties of source footage, project properties and render properties. If render properties must be different, render to an intermediate or a new track.

...Jerry

Is this a standalone?