I'm having a similar problem to one of the other 3 monitor topics. I have 3 monitors (1x 46-in and 2x 32-in) all Panasonic. Only 2 of the monitors are allowed to be extended at the same time. Any combo of 2 works, and all 3 are being recognized, but the
third monitor is disconnected. The issue appears when I try to enable (extend/duplicate) a third monitor. After I extend the third monitor and hit "apply", I get a message that says "cannot not save current settings". It will allow me to duplicate the third
monitor to either the first or second, but automatically disconnects the monitor that wasn't duplicated. For example: duplicating 3 and 1 will disconnect 2; duplicating 3 and 2 will disconnect 1.
I didn't have this problem til recently, and I have used all three monitors in extended display. The only known change I can think of was a switch from VGA cables to HDMI. I've tried switching back to VGA but with no results.
In most case, error message “cannot not save current settings” means the screen resolution for the three monitors are different. Make sure that you have the same screen resolution for all
Also, ensure all the latest Windows Updates are installed including the latest Display drivers.