MacBook won't send video signal to external monitor after waking up

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Okkipokki Author

Level 1

8 points

MacBook won't send video signal to external monitor after waking up

The external monitor (34" MSI PS341WU) is connected to my MacBook (Pro 15" 2016, MacOS 10.15.3) via usb-c.

It works fine, except when my MacBook wakes up from sleep.

The monitor wakes up, but shows the message 'USB-C No Signal'.

Only when I quickly unplug and plug the usb-c cable, the monitor shows my desktop again.

I found a few other similar questions, but so far, none of the answers solved it for me (plugging the usb-c into the other side of the MacBook, reversing the cable, trying another usb-c cable).

Help!

MacBook Pro 15", macOS 10.15

Posted on May 4, 2020 3:12 AM

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Answer 1

Best reply

Okkipokki Author

Level 1

8 points

May 5, 2020 6:33 AM in response to a brody

Hi Brodi,

thank you again.

Your description is a bit confusing.

My MacBook has two usb-c sockets on both sides (and no regular USB sockets at all).

Anyway, I started swapping the plugs around and lo and behold: I found a working solution!

See below.

Just out of sheer curiosity: Is that what you meant?

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Answer 2

a brody

Level 10

83,353 points

May 4, 2020 5:59 AM in response to Okkipokki

Many of these adapters are underpowered for their functionality. Using a USB-C adapter with its own external power source makes a difference.

You can also try turning off put hard disks to sleep in your Energy Saver preferences, but that does not always work. Apple's low power mode for USB messed up bus powered USB devices. Restarting the computer is the only to overcome it with devices that are bus powered.

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Answer 3

Okkipokki Author

Level 1

8 points

May 4, 2020 6:52 AM in response to a brody

hi Brodi,

thank you for your reply.

The thing is: there is no adapter involved.

All there is between the MacBook Pro and the monitor is a usb-c cable.

And both the MacBook Pro and the monitor have their own separate power cable.

(the monitor does not support powering the laptop over usb-c)

I tried turning off the hard disk putting to sleep option in energy saving settings, but no luck.

So far, I’m still unplugging and inserting the usb-c cable every time I return to my desk.

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Answer 4

a brody

Level 10

83,353 points

May 4, 2020 9:35 AM in response to Okkipokki

Two possibilities:

On laptops where the sides are

USB-C back left and/or USB back right

USB-C front left and/or USB front right

Swapping the front and back power cord & the USB-C video adapter positions works from front to back.

Adding a USB-C video hub that has a passthrough for USB-C power works, such as this one:

https://www.monoprice.com/product?p_id=15758&gclid=EAIaIQobChMI37SSk9Ca6QIV44NbCh09qgHZEAQYAiABEgJ0d_D_BwE (allows you on the USB -C port to plug the power cord straight from your wall outlet USB-C adapter on the left hand port)

Any adapter with PD Passthrough should work.

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Answer 5

a brody

Level 10

83,353 points

May 5, 2020 6:42 AM in response to Okkipokki

Based on the image, you will run a USB-C cable from 0 to either 9 or 7 depending on what fits, and then connect 6 to either 3 or Then your monitor should be to link 5 to 8. Since your alternative works, I would not mess around!

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