This worked only after going into the curves file and changing the permissions. It seems that the OS update to Sonoma defaults to “read only” for the downloaded .quad curve files which prevents them from being installed. Saw this on the QTR forum after unsuccessfully trying the terminal command. It seems that it only affects newly downloaded or created .quad curves. As Apple continues to “evolve” the OS I hope that these surprises will be avoided.
Thanks
Berel