I have an iMac that I use as display for my mac pro. Until upgrading to macos sierra, everything worked fine. After upgrading both machines to the latest release of macos sierra, two bizarre things have happened: first, cmd-f2 switches displays, but the mac pro display now remains black. I can use "remote desktop" to connect from one machine to the other, but nothing I do allows me to use the full screen; the remote desktop window (and the shared display window) cannot be made to be larger than about half of the horizontal width of my 27" iMac. This is not fun! any suggestions on what to do? as mentioned, I changed absolutely nothing except the OS; went from el capitan to macos sierra and no other changes, hardware or software, made to either machine....target display mode just stopped working, and remote desktop is an unusable small screen on the iMac.
target display mode
Agreed, I observe identical problem. As well the airplay mirroring to apple TV fails in a similar fashion no output on the apple TV.
So, is this feature no longer supported in Sierra? It would be nice to hear an official response from Apple on this issue.
I sometimes get black screens in El Capitan when entering target display mode, I just need to reboot the source machine (in my case it's a PC), and then it works fine. Have you tried rebooting the Mac Pro and then enter TDM again?
Airplay mirroring was fixed by the released build. The issue seems to be a bug, I'm working this with Apple support guy.
Seems to be, reboots neither SMC or NVRAM resets help.
I've just had a chat with Apple Support, and the guy on the other side assured me that Target Display Mode is fully supported on MacOS Sierra... 😕
Maybe it's some kind of bug...
I'm having the same issue and freaking out now. This is my work computer. Even if they fix the bug, how can I fix it on my computer if I can't even get into it?
Just an update: I've finally installed macOS Sierra (clean install). The Target Display Mode works fine on my system: iMac 27 mid-2010. I've tested it with a PC connected to the mac through a mini-DisplayPort to DisplayPort cable.
no change. problem with black screen survives reboots (hard) and upgrading to developer beta 2. it is as if the mouse and keyboard that used to be attached are no longer there, so the display can't be woken up.
Just wanted to make sure that folks knew that the black screen (which is my screen saver) cannot be interrupted using the latest release of macos sierra developer beta 2 on both machines. When I connect to the mac pro using ARD, the wireless mouse keyboard are alive and well and work as expected. When I use target display mode and switch displays, the macpro display remains black, regardless what I try to do with the input devices.
I upgraded yesterday and confirm this is still happening.
Any update on this issue? Having the same problem with my Mac Pro and iMac
Having the same issue on seemiongly random macs, the developer page for preferences still lists com.apple.airplay.plist as being a place where airplay settings are stored. This documentation needs to be updated for macOS Seirra as this is currently not the case. I do not have this .plist in either my user or system library. Can someone update where this is now being stored. We can send Video and Audio, just no airplay mirroring.
I am trying with a new user to see if this is user based or OS based. Also going to try with same hardware but external disk with a clean OS.