OS won't detect second monitor

[raymm]

I have an HDMI cable from my computer to an HDMI splitters, then cable to two monitors.  I have an image from the computer, cloned on both monitors.

I'd like to extend my desktop across both monitors.

Under Settings - Display - Multiple displays - "Didn't detect another display.

I've refreshed my driver for my NVIDIA GeForce GTX 1060 3GB.  Date 2017-10-27 23.21.13.8813.

I've rebooted. 

Won't detect, even though I see the clone on both monitors.

I'm hoping someone can give me a clue on what I can do to get second monitor detected. And to extend desktop across both monitors.

[TheOldMan]

I suspect the reason to be the HDMI splitter is interfering with the communications between desktop and the monitors that Windows needs.  Try removing the splitter and just connect one of the additional monitors to see if Windows can then communicate with the second monitor.

Some of the splitters will send the monitor info connected to output #1 back to Windows so you can get that to work.  It must be the one you are using either does not do that or it does not have a monitor on output #1.

Report with results.  It might be a good idea to identify the make and model of the splitter in use, here.

[raymm]

Splitter = Rocketfish 2 - Output HDMI Splitter 4K Ultar HD and HDR compatible.  "Splits one HDMI signal into two outputs."

RF-G1603 / RF-G1603 -C

https://www.bestbuy.com/site/questions/rocketfish-2-output-hdmi-splitter-with-4k-and-hdr-pass-throug...

[TheOldMan]

Did you try without the splitter, as I suggested, just to test?