Export multitrack mixdown greyed out

had the same problem. Just change the output for each track to "Mix" and you'll be able to export w/ multitrack mixdown.

Replying direct to the poster. Change your "out" on each track to MIX. This should allow you to export entire session. I just figured it out for myself.

You haven't said whether this is on a PC or a Mac. There have been a couple of reports of this happening on Macs but none on PCs, and certainly here on a PC the export options are correctly displayed in Multitrack. The other complaints are also about exactly the same option being missing.

There are a few things to try: Try copying the files into a new session and see if the same thing happens - this is just an attempt to find out whether a corrupted session file is behind this (we've asked others to do this but not had any definitive response from them). If it's just the same, then it's possible that a corrupted Preferences file is to blame. Unfortunately the cure for this will remove any custom settings you've made, but it's easy to implement - you just stop Audition and restart it with the Shift key held down. The most comprehensive way of resetting Audition is to clear out your installation using the CC cleaner app instead of the Microsoft uninstaller and then reinstalling, but that really is a last-ditch solution.

One of the problems here is that if this was a genuine bug as such, there would be loads of complaints about it - and apart from a few Mac ones, there haven't been. This makes it rather hard to determine whether it actually is one or not. If none of the above works for you, it might well be worth reporting this on the Audition Beta forum, where the developers are far more likely to see it, and perhaps respond...