Simplest, imo, copy the link from the email and paste into incognito tab/window. Otherwise...
A couple of things to try.
First, launch Chrome in Terminal using the incognito switch, keep it running. Click email link and see if it goes to that instance of Chrome.
Code:
open '/Applications/Google Chrome.app' --args --incognito
If that does not work, can try messing around with the application bundle and have Chrome always launch in incognito (don't really recommend this, but if desperate):
- Go to /Applications/Google Chrome.app/Contents/MacOS
- Rename 'Google Chrome' to 'Google Chrome.exe'
- Create a shell script that will run the 'Google Chrome.exe'
Code:
#!/bin/sh
'/Applications/Google Chrome.app/Contents/MacOS/Google Chrome.exe' --incognito &
exit 0
With this, can probably install two copies of Chrome, "real" and then the modified one (can probably name it something else), and then select the default browser in Settings to be the modified Chrome. Unfortunately, do not think there is a way to set default browser for just mail.