Audition. Complex project slowing down

While there are numerous helpful pieces of advice (especially SteveG's advice regarding fx) in this thread in my experience these 3 points should be the most helpful.

1. DO NOT have your session (and more importantly your media) on an external drive

2. Have your session (and more importantly your media) on the fastest internal drive available

3. Preferably have your temp file locations also on internal fast drives (if not both at least the primary one but also don't have them on the same drive)
Failing all this try freezing (pre-Render) some of your tracks

One of the most common reasons for massive slow-downs on sessions is the number of effects applied - especially if they are processor-intensive ones. If this is the case, then you need to pre-render the tracks with the heavy effects. You can undo this at any point to remake things - it's not destructive. Just to remind you (!) there's some more info (and a couple of things to be careful about) here. 

Hi.

Have you tried saving the file, closing Adobe Audition, and restarting your computer? That usually solves it.

Other things to watch out for when editing slows include:

• Make sure you're editing from your local drive rather than an external (externals usually work, but it can be slower)
• Make sure Time Machine isn't actively backing up, especially to that same drive containing the media files
• Close all other applications
• Are you editing the audio track of a video file?
• Is it only Audition, or are other applications slowing, too?
• Does it only happen with one file?