The display and cable were working, it was the Mac that got into a state where it could not see external Thunderbolt devices. Given all my troubleshooting I believe the culprit was the Mac itself. At this point I was in the simplest configuration: display connected directly to laptop and no docking station. I finally tried powering off the power strip and powering everything back on at once. The aggregate of the successful answers here suggested this was a power sequencing issue. In my case all the troubleshooting loosened the plug into the docking station transformer. Similarly the monitor has a cord with two ends, make sure both are snug. The docking station has a transformer which plugs into the power strip and then the transformer plugs into the docking station. Power cables: I know this sounds stupid, but check each point in the power chain.The hardware I had been using for the last couple of weeks successfully (display, docking station) had no changes. Recent history: Nothing changed on my computer (at least that I initiated).Googled to find the magical hidden Apple button to detect external displays (System Preferences -> Displays -> hold down Option button to cause magical button Detect Displays to appear), nothing detected. Power cycled display on boot it reported no DP device detected. Detection: Try having each side detect the other.Power cycle display while connected to computer (didn't work). Reboot computer with display connected (didn't work). Connection sequences: Tried rebooting computer with display disconnected, connect display to computer directly (didn't work).Before I eliminated the docking station I was able to see the CalDigit connected and supplying power, but no display connected even though the display was connected to the CalDigit. lets you see the Mac's view of what is connected. Diagnostics: Apple -> About this Mac -> System Report.Drivers/OS updates: It was a working and stable configuration for some time, with no intervening updates before it stopped working, so don't destabilize the environment by changing drivers before troubleshooting.So plug in your computer using its power supply. In other words computer may disable hi res displays on battery power. Confirm power: I have seen references that higher resolution displays cannot be supported without direct power for your computer.Confirm computer: reboot computer, try plugging, unplugging display into computer (didn't work).disconnected docking station, connected display directly to computer (didn't work) Simplify: eliminate everything in the chain possible, get it working then add back.Confirm display cable: didn't have another USB C computer to connect to (skipped).Confirm display: connect to another computer (worked).The basic troubleshooting strategies applied were: I spent HOURS today trying every combination of troubleshooting under the sun. CalDigit TS3 Plus with Thunderbolt 3 cable.No display -after weeks of this sequence followed successfully, and new gear (one month old display, cable, docking station). The only crime I did was to unplug the Mac from the dock and plug it back into the dock later. The same malaise hit my external monitor today. On a cantankerous note, I feel obliged to note that the prevalence of this issue (assuming a google search is representative) is disappointing given the expense and corresponding implication of quality of Apple hardware. Since the first time I stumbled on this solution, the MacBook has repeatedly failed to detect the external monitor (usually a few days after the issue last occurred) and these steps have resolved the problem every time. Wait for the MacBook's screen to briefly flash black.Plug the monitor's HDMI cable back into the multiport adapter.Turn off the monitor (it was not necessary to unplug it).Unplug the monitor's HDMI cable from the multiport adapter.I confirmed that the monitor and HDMI cable were fine by connecting them to another computer, tried two different multiport adapters ( this one from StarTech and this one from Anker) in all four Thunderbolt ports (notably, all the non-HDMI ports on these adapters have consistently functioned without issue), reset the NVRAM (as suggested in Apple's troubleshooting instructions for external displays), and tried power cycling the monitor as suggested in the top answer. I recently experienced the same issue: a new work-issued 16-inch Macbook Pro stopped recognizing a Dell monitor connected using an HDMI cable and a multiport USB C adapter.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |