I cannot consistently extend to my external monitor with my laptop. Most of the time it does not work. Occassionally it will work and I have no idea what I did to cause it to work.
Here are some observations:
1. If I boot up with a monitor connected, it will use the external monitor and I cannot switch back to my laptop monitor.
2. I have used 3 or 4 different external monitors including a projector with the same results.
3. If I boot up with no monitor connected, then connect, the external monitor is black. When I go to the screen resolution window, there is no option for multiple displays. If I click on "Connect to projector" and select extend monitor, it returns me to the main Screen Resolution Window and now my monitor is listed in the drop down for display and the "Mullitple Display" Option is there with a drop down to "extend these displays" If I select extend these displays it shows a yellow triangle and the message "You must select apply before making additional changes". When I click apply, an error window pops up saying "Unable to save display settings". Now i am in a vicious loop.
4. However, once I have done this, I can now make my external display the display... I can switch over so it is the one I see. Once I do that, I cannot go back to my laptop without rebooting.
Crazy, huh? Any ideas of what I am doing wrong?