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Multiple monitors issue

I have 2 monitors linked to my Mac Pro 15" (macOS Catalina) and I have connected a hub (USB-C) with which I had both monitors connected by HDMI. Once both connected by HDMI only 1 monitor would display the screen.

In the end I had to connect 1 monitor via USB-C and 1 by HDMI off the hub. So, with the laptop screen active, I have the left monitor (connected by the USB-C) as mirror to the laptop and the right monitor connected by HDMI through the hub as the extended display. The hub is connected by USB-C to the laptop and that seems to work OK.

I then close the laptop screen (after changing the setting for display close sleeping) and the monitor order is swapped around - that is mirrored monitor is now left and extension is the right monitor.

However when I goto battery power (that is disconnect the power connection via the hub) with the laptop closed the monitors go blank and nothing is visible.

Then if i open the laptop the displays appear again in the correct left mirror, right extended format.

Close laptop and apply power through hub - monitors appear in left extended and right mirror format.

I have tried various hubs to try and settle this issue but to no avail.

I need some form of hub to use USB 3.0/3.1 thumb drives and such, as my space for the laptop is limited on either side - hence the use of a hub.

One question is could I use 2 thunderbolt ports for monitors - i think most I have read indicates it should be 1 thunderbolt and 1 HDMI.

Any help appreciated

Ron

MacBook Pro 15”, macOS 10.15

Posted on May 13, 2020 1:52 AM

Reply
Question marked as Top-ranking reply

Posted on May 13, 2020 2:29 AM

RonAbes Said:

"Multiple monitors issue: I have 2 monitors linked to my Mac Pro 15" (macOS Catalina)[...]I have tried various hubs to try and settle this issue but to no avail.[...]"

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Reset the SMC and NVRAM:

Sometimes changes are made to the system and then settings (i.e. for hubs) become manipulated, technically.  So, with so many monitor issue scenarios, reset both on your Mac.

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3 replies
Question marked as Top-ranking reply

May 13, 2020 2:29 AM in response to RonAbes

RonAbes Said:

"Multiple monitors issue: I have 2 monitors linked to my Mac Pro 15" (macOS Catalina)[...]I have tried various hubs to try and settle this issue but to no avail.[...]"

-------


Reset the SMC and NVRAM:

Sometimes changes are made to the system and then settings (i.e. for hubs) become manipulated, technically.  So, with so many monitor issue scenarios, reset both on your Mac.

May 13, 2020 3:08 AM in response to RonAbes

RonAbes Said:

"Thanks but no success after resetting both SMC & NVRAM."

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You are welcome.


Boot into Safe Mode:

Booting into Safe Mode (hold down the shift key upon boot), particular items will be fixed, and items will only run as they would by default, being that Preferences are set aside. So see if booting into Safe Mode fixes this.

Multiple monitors issue

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