100% CPU Usage when mixdown

Hey @Nico5
I think I found the issue.
thank you very very much for your help!

I tested this project on my side, and to my surprise I had in C12 a CPU usage of about 44% average on mixdown and the elapsed time was about 10 seconds.
I then created the exact same project from scratch and had the 100% usage again and an elapsed time of about 14 seconds.

The only difference I noticed was the sample rate and that seems to be the cause of the issue in C12.
If the project sample rate differs from the mixdown sample rate, all cores go on full load and the export time is multiplied.
Thats probably why some have the issue and some not. Those who work with the same format in their project as the mixdown format, wont have any issues.

Can you please try to set your project settings to 48kHz and retry to mixdown a 44.1 kHz file?