There is a specific article for Live in the Ableton Knowledge Base:
To set your DAW to open using Rosetta, you can follow the steps shown below for Logic Pro.
- close your DAW, if it is running
- find the application in your Mac
- choose File > Get Info
- tick the Open using Rosetta checkbox in the info window (shown here for Logic Pro)
- you can now close the Info window for your DAW; it will open in Rosetta mode at next launch
Your DAW will then open in Rosetta mode and VocAlign will display the Capture button for the Guide track, as expected.