External display connected via USB-C > VGA goes to endless sleep/wake loop

Question

I have a dell external display connected to my mb pro 2017 (Mojave), but whenever i try to sleep my mac (with sleep command), it goes to endless loop trying to sleep and then immediately wakes up, because external display won't sleep.

Is there any workarounds / apps to prevent this behavior?

How do you know it is the display ? does it sleep if your turn it off ? — Ruskes, Dec 22 '18 at 02:32
if i turn off the monitor, mac still thinks as it's on and won't sleep, strange behavior. — Alexander Kim, Dec 22 '18 at 08:07
Yes, i've noticed if i use sleep on external display's menu, then both macbook and external display would go to sleep as intended, but if i use sleep on a macbook itself, then external display won't sleep. — Alexander Kim, Dec 24 '18 at 02:41
It's probably the USB-C(DisplayPort) to VGA adapter. Try using an active adapter so that it recreates the actual VGA signals. — Allan, Dec 24 '18 at 13:34

score 1 · Answer 1 · answered Dec 24 '18 at 11:12

1

I just had to put the mac in to sleep using external display. Also closing the LID won't work, you have to sleep the external display first, then you can close the LID.

answered Dec 24 '18 at 11:12

Alexander Kim

478

score 0 · Answer 2 · edited Jun 15 '20 at 08:04

0

First run the pmset -g in Terminal

PMset is the Power Management settings.

to see your settings.

Then reset those settings to Defaults with

pmset -c 2 -b 1 -u 1; pmset -g

To find out who is actually keeping it from Sleep use pmset -g assertions

The report in Terminal looks like this example (without Sleep problems)

From this (yours) report we should see what is preventing the Mac from Sleeping.

edited Jun 15 '20 at 08:04

Community

1

answered Dec 22 '18 at 04:35

Ruskes

48,129

That's not the issue. I know about pmset, thanks. – Alexander Kim Dec 24 '18 at 02:42
@AlexanderKim I was trying to help and you did not disclose that in your post. – Ruskes Dec 24 '18 at 03:13

External display connected via USB-C > VGA goes to endless sleep/wake loop

2 Answers2