I have 2 computers, a desktop HP and a notebook ASUS. As of this morning they do not detect the secondary monitors attached to them. Yesterday they were working fine in multi-monitor mode. I will shortly be trying all the multiple-monitor detection suggestions in your previous discussions. I'll be back once I have exhased all corrective action suggestions. I am resonably sure the problem is a recent Windows 10 update, as no other changes occured since this were functioning correctly.

Friends suggested I reboot. Since I had just done that it did not seem effective, but I tried it.

VOLLA - problem resolved. It seems that the Windows update required 2 reboots before it released my system to full functionality.

To clarify. The multi-monitor detection is reinstated, it took turning the computer on and off twice after the windows 10 update.

i had a similar issue as well after doing a clean install of win10 anniversary where it wouldnt let me reorder my 3 monitor setup. i dont know if this is the same issue or not. i just decided to use the nvidia controls to change the order of my monitors.