Unable to connect external display to MacBook Pro (Viewsonic VG2755)

jeroen209 wrote:

• I have tried to connect the display in 2 ways

USB C - USB C cable (cable provide with Apple charger)

• USB C - USB adapter (from Apple) + USB - USB to monitor

However this is not working.

In parallel the MacBook is charging via another USB C port.

Already restarted MacBook, used the "detect displays" in system preferences.

You do not say what exact Mac /model /year /size /retina /touchbar is this ?

or

what types of external display you are trying to attach?

The USBC that shipped with your Mac is a charging cable only —not high speed data transfer. (The Apple USB-C Charge Cable supports charging, but data-transfer speed is limited to 480Mbps (USB 2.0) and it doesn't support video.)

Identify the ports on your Mac - Apple Support
 https://support.apple.com/en-us/HT201736

Get help with video issues on external displays connected to your Mac - Apple Support
 https://support.apple.com/en-us/HT201177

Best results for that display will be achieved by connecting with a USB-C to [Full Size] DisplayPort cable (not included). The USB cable included is for additional peripherals hung off the display,-- it can not run the display itself.

USB-C is the name of the distinctive reversible connector, not the cable.

In sharp contrast to the way Apple devices and connectors used to work, any cable with the proper connectors is not guaranteed to do ANYTHING. You must pay extremely close attention to the name of the cable printed on the box.

The classic counter-example is the Mac charge cable. It has power and USB-2 only, not fast enough for much more than a keyboard, and way, way, way too slow to run a display or a drive of any description. But it has USB-C connectors at both ends!

I opened another thread about a similar issue with an external display (Viewsonic VG2755)

You can see it at: https://discussions.apple.com/thread/250376623

I got a no signal issue with Viewsonic VG2755 display after updating to Mojave 10.14.5. With Mojave 10.14.4 it was working ok using a USB-C cable.

Thanks for the reply but It's not a cable issue. Everything was working Ok before the upgrade to Mojave 10.14.5.