How to ignore Spotlight index for a volume contain another macOS Volume A: macOS A
Volume B: macOS B


How can I ignore Spotlight index of Volume B when using macOS A, while keeping index data and use index when switching to macOS B.
Launch System Preferences
Select Spotlight
Select the Privacy tab
Add the tab of the volume that should not be searched (NOT the one you've booted from)
Wait a minute - ensure the change gets written to disk
Reboot