I appreciate the many good ideas and suggestions. After two hours on the phone with Apple support I concluded it was time to give up laptop color with external monitor. Seems that during 2008 Apple sold an evolving variety of 17" MacBooks. Some use two color cards, some make both displays share one card. The Apple fellow had never heard of Color Munki, which is what I am using for hardware profile. He made many suggestions, none of which helped, but which left me with many problems to solve, like re-establishing hundreds of critical prefs whose loss crippled my softwares.
The problem devolved into a worse one: every time the computer went to sleep or was restarted, the monitor would turn dark and yellow. I could cure it by a fresh profiling, which meant profiling each time I sat down to work.
No help from Apple, because LaCie and Color Munki are third party. No help from LaCie because my LaCie sensor has been in repair for some months and they won't discuss Color Munki. No help from Color Munki because they don't respond.
No help from my local dealer and color management consultant. (They did offer to sell me a nice new $5000 top of the line tower Mac.)
So I went out and bought a used tower Mac fo $1700, spent the day fighting through re-install of Adobe CS Premium Suite and Lightroom. New system is much faster than my laptop, and one day when I get my Blue Eye back, I will profile the monitor and can get back to work.