ACID Pro 6.0 software does not include track freeze, though it can render to a new track or render to your hard drive.  “Freeze” is essentially rendering of selected tracks that can not be undone. This is usually only used when your computer has been bogged down from too much audio processing. Like any render, it is a time-consuming process. ACID can render out portions of a project, however the render can not be reversed or undone, since we create new files in the process.You can always delete the files that are created from the render though.

To render just one section of the timeline, select the area of the timeline that you would like to render by left clicking above the ruler at the top of the timeline, hold down and drag to the right. Keep dragging until the entire area of the timeline is selected that you would like to render. Then right click on the bar that indicates this area (with yellow corners) and select Render to new track. To render that area just to your hard drive rather than also adding it to this project, go into the File menu, select Render As, and check the box to Render the Loop Region Only at the bottom of the Render As window. Name the file, select the Save As Type, and direct the file to where you would like it rendered on your hard drive, then press Save. You could then bring the rendered file into a new project if that area was all mixed properly and continue on with your project saving system resources in that new project.