Hello Christopher, here the answers to your questions. I hope it helps.
1) What release did you upgrade from where this problem wasn't reproducible? I was using the 14.04 (stable) beforehand and I can't recall having this problem. Another thing is that I recently switched from a HDMI-DVI to a HDMI-HDMI cable. To my knowledge the problem didn't occur with the HDMI-DVI cable (even the sleep and suspend feature was working without any problems). 2) In the prior working release, were you using the nvidia proprietary drivers? Yes, I was using the nvidia proprietary drivers. 3) If you uninstall the nvidia proprietary drivers does this provide a WORKAROUND? If I'm not to use the proprietary one the issue is even more persistent. Xrandr is showing the second monitor as connected, but even a restart of the lightdm service doesn't help. The monitor always shows "no signal". -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1607212 Title: HDMI connection issue (Ubuntu 16.04 and GeForce GTX 960M) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1607212/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs