I have a 15" macbook pro with 4 USB-C/thunderbolt 3 ports. I bought a multiport adapter from USB-C to HDMI and also a U2417H dell monitor which has 1 DisplayPort, 1 Mini DisplayPort and an HDMI port.

Every time I plug my mac into the monitor, I have to reboot it. Sometimes however, the mac will recognize that it is connected to a Dell monitor, but the monitor stays and with the message "No Signal."

I haven't tried a USB-C to HDMI cable or a DisplayPort adapter or cable because I want to ensure that there is not an issue with the monitor before I buy anything else for it.

The monitor works fine with a windows machine using the same HDMI cable.

What could be causing my monitor to have these issues?

  • Did you find a solution?
    – LiweiZ
    Commented Jul 20, 2017 at 4:07

2 Answers 2


I have same problem with MBP 2017 15" with plain Full HD monitor. MacOS always says it is connected but no signal to the monitor.

As Jackson1442 says, rebooting sometime works but not all the time.

My MBP 2014 has no problem so I doubted my hub and then the hdmi cable. I replaced those but no changes.

I now doubt about 2017 model itself as Mohannad Kattan mentioned. It is so annoying.

I will try USB-C to HDMI cable without hub.


I have LG 4K monitor with DisplayPort and MacBook Pro 13" 2016 with Touch Bar and I'm using them together since I bought the MacBook Pro, today I got MacBook Pro 13" 2017 and I tried to connect it with my LG monitor, but it didn't work, I returned my old MacBook and it worked. I went to Apple store because I thought the MacBook was defective. The apple genius agent connected the Mac to a Dell monitor with USB type C and it worked immediately. I think the DisplayPort adaptors are not supported with the new MacBook versions. Update: I updated my MacOS High Sierra because I thought it was a software issue, but that didn't fix the problem.


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