2018 Mac Mini Static after sleep awakening

RedGuest99

macrumors newbie
Original poster
Dec 20, 2018
10
11
I'm having the static/snow screen display issue after awakening from sleep on my 2018 Mac mini. By static/snow, I mean the monitor display looks like the pattern an old TV using an antenna would display if it lost its signal. I returned my first 2018 mac mini because of this issue and the replacement 2018 Mac mini has the same issue. What I've learned about this issue is documented below. Apple tech support is not experienced with this issue, so, in the near term, it's up to the community of users to figure this out. Please add any knowledge or experience you have with this issue to this discussion.

My 2018 Mac mini set up:
OS version as of this post: Mojave 10.14.2. The mini is connected to two Samsung C24F390FHN monitors. One monitor is connected via an HDMI cable to the HDMI port on the mini and the HDMI port on the monitor. The other monitor is connected to a USB-C port on the mini and the HDMI port on the monitor.
Issue Observations:
  1. The static/snow display issue ONLY occurs when the mini awakes from being in sleep mode for a longer period of time. Clicking the Apple icon in the upper left corner and choosing "Sleep" and then waiting 4 minutes is long enough to cause the issue to appear.
  2. The issue ONLY occurs on the monitor connected to the HDMI port on the mini.
  3. The monitor connected via the USB-C port on the mini does NOT exhibit the snow/static display issue upon awakening from sleep mode.
  4. I isolated the issue to the HDMI port by switching how the two monitors were connected to the mini; either via HDMI or USB-C. Since the issue followed the HDMI port and not a specific monitor, this means either monitor is NOT the source of the issue. This issue is directly tied to the HDMI port on the mini.
  5. The issue fixes itself after less than a minute. The screen switches multiple times between displaying snow/static and a black screen and then eventually fixes itself.
  6. Disconnecting the HDMI cable from the mini or monitor and then reconnecting the HDMI cable also fixes the snow/static issue.
  7. Apple's tech support recommends three standard resets (PRAM, SMC and another acronym I don't recall), which do nothing for this issue. Don't waste your time performing these resets.
  8. Apple's tech support escalation process is ineffective for this issue. The third contact on my support case for this issue resulted in a Genius appointment that was a waste of time. The Genius stated that unless they can replicate the issue, the issue is likely specific to my computing environment. Rather than leave the mini at the genius bar for a few days, I chose to return the mini (it was only a few days old) thinking the issue was likely an anomaly only associated to the particular unit I had. That's not the case since my replacement mini has the exact same issue. My Apple tech support experience gave me the impression that since the 2018 Mac Mini is so new, Apple just doesn't have enough experience with this issue yet. Don't waste your time with a Genius appointment. You may even want to consider holding off on buying a 2018 Mac mini until this issue is figured out.
My next steps to get around this issue include:
  1. Try connecting both monitors via a USB-C port. As in, don't even use the HDMI port on the mini. This requires buying a new cable.
  2. If step 1 above doesn't work, then try using the HDMI port or a USB-C port on the mini to connect to the monitor via the VGA port or whatever other connection is available on the monitor besides the HDMI port. This requires buying a new HDMI to VGA cable or similar cable.
Updates as of 01-16-2019.
Both of my monitors are now connected via USB-C cables on the mini to HDMI ports on the monitors. Doing this replaced the snow issue after wake up from sleep with pure black screens being displayed on both monitors for 20 seconds after awakening from sleep. Yes, there's an annoying 20 second wait EVERY time I awaken the mini from sleep. I also tried using an HDMI to VGA connection for one monitor. This didn't work at all. Don't waste your money trying this. The monitor connected via the HDMI to VGA cable would just constantly blink.

Having been through the Apple tech support process, Apple thinks the issue is a Samsung monitor issue (of course it can't be an Apple product issue...;)). Apple suggested everything from rearranging cables (possible electromagnetic interference issues) to trying new cables, which I tried. I then contacted Samsung tech support and described the issue, and yes, you guessed it, Samsung says it's an Apple product issue. Getting nowhere, slowly. Anyway, I borrowed an LG monitor and.....yes, the same issue exists with the LG brand of monitor. I think the Monitor, Cables and Cable Arrangement can be eliminated as possible causes of the issue. The comments from others left below reporting the same issue using different monitor brands (Acer, LG, HP) adds more data points suggesting that the monitor is NOT the issue. I've reported this information back to Apple tech support and they seem to have gone silent. Hmmm? What's left to check? Perhaps the mini itself? To be continued...dah-dah-daaaaah!

Update January, 23 2019:
Installed OS 10.14.3 with no change. The issue still exists and so does my Groundhog Day-like experience with Apple support. No communication back to me yet again. I guess I have to contact them and start all over again...interesting technique. Less than impressive experience.

Update March 7, 2019:
I've given up on hopes of Apple support coming up with a solution for this issue. The continuous lack of progress in finding a solution has worn me out, which the jaded part of me suspects may be have been the Apple support strategy all along. Someone else will have to take up the cause and contact Apple support. See my comments in a post below as to how a tech support case for this issue will be handled by Apple. My impression is that Apple is focused on other things and the lowly mini is a low priority. I've learned my lesson. Based on this experience, I will definitely begin diversifying the operating systems within my "computing environment" as Apple refers to it.

Update June 5, 2019
I continue to live with a "20 seconds of black screen" wait EVERY SINGLE TIME I awake the mini from sleep. Clearly this bug is a low priority for Apple, but Apple should realize that experiencing this bug multiple times a day EVERYDAY adds up to a LOT of negative experiences that myself and others will associate with the Apple brand. As of this post, I'm currently using macOS Mojave 10.14.5. And yes, I'm calling this issue a macOS software bug so others don't waste any time or money on genius bar appointments that won't resolve the issue, tech support phone calls that won't resolve the issue or buying new monitors/cables that won't resolve the issue.

Update September 5, 2019
I installed macOS Mojave 10.14.6 with no change to the faulty wake from sleep behavior. What's interesting is that immediately after each OS update the first two or three wakes from deep sleep occur in under three seconds or so, but the twenty second wait of black screen immediately returns thereafter. It's as if the programmers are teasing me with false hope only to pull the football away at the last second like I'm Charlie Brown. That's an arcane Peanuts comic/cartoon reference for non-American readers of this post. I think there's enough information within this thread for Apple to fix this issue, but I fear a corporate cost-benefit analysis has determined the costs of fixing this issue are greater than the benefits to Apple. It's also interesting that my own personal cost-benefit analysis of remaining in the MacOS ecosystem has come to the same conclusion of costs being greater than benefits. Perhaps me and Apple are in agreement on something.
 
Last edited:

harriska2

macrumors 65816
Mar 16, 2011
1,266
639
Oregon
It seems usbc and displayport have issues. My hdmi 4k doesn’t. I also have computer sleep turned off but do have monitor sleep turned on. No issues with my Samsung 40” 4k monitor.
 

InformationLandmine

macrumors newbie
Jul 18, 2017
1
1
Try having just a single monitor connected via HDMI and see if it still happens. That would be a useful data point. Also try a different monitor completely to see if it's related specifically to how the Samsung is handling the HDMI signal from the Mac Mini.
 
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harriska2

macrumors 65816
Mar 16, 2011
1,266
639
Oregon
Try having just a single monitor connected via HDMI and see if it still happens. That would be a useful data point. Also try a different monitor completely to see if it's related specifically to how the Samsung is handling the HDMI signal from the Mac Mini.
What he/she said.
 

RedGuest99

macrumors newbie
Original poster
Dec 20, 2018
10
11
Well, I just received a second USB-C cable for connecting the second monitor and.........I can now state that not using the HDMI port at all on the 2018 Mac Mini removes the snow/static issue post awakening from sleep. Both of my monitors are now connected to the Mini via USB-C ports. The only difference I notice now is that awakening both monitors after sleep takes a full 21 seconds (I timed it) after clicking the mouse to wake up the mini after a deep sleep (as in sleeping for over 5 minutes or so). Yes, 21 seconds from mouse click to non-black screen. Is that a normal amount of time for a Mac to awaken from a deep sleep? The awakening time from a short-sleep (less than a minute) seems normal and has not changed...maybe a few seconds.

It's a bummer that the Mini's HDMI port isn't 100% functional at this time. The HDMI port on the mini works fine at all times EXCEPT when awakening from deep sleep. I've asked Apple to escalate my case and help determine how this can be rectified.

I haven't tried the single monitor only setup since there are other threads on this site (and other sites) that have reported the same snow/static awakening from sleep issue with the 2018 Mini HDMI port with a single monitor connected. So those data points are out there.
 

harriska2

macrumors 65816
Mar 16, 2011
1,266
639
Oregon
Yeah, it's why I turned off computer sleep altogether. I only use monitor sleep. It takes about 2 seconds to get the Mac mini back up after switching to a different computer on my monitor (the monitor allows 4 cps to be attached and can switch between them with a remote control).
 

Spectrum

macrumors 68000
Mar 23, 2005
1,622
937
Never quite sure
I'd be suspicious of the HDMI cable. Also, you, unfortunately, haven't proven that the issue isn't isolated to that particular model of Samsung display.
 

harvester32

macrumors member
Oct 29, 2012
45
28
It's not just Samsung...I have an ACER K242HL attached via HDMI and it exhibits the same symptoms. Even bought a new "premium" cable to see if that changes the behavior and it does not.
 

Spectrum

macrumors 68000
Mar 23, 2005
1,622
937
Never quite sure
It's not just Samsung...I have an ACER K242HL attached via HDMI and it exhibits the same symptoms. Even bought a new "premium" cable to see if that changes the behavior and it does not.
Well that doesn't sound good. All I can report is that I don't see the same thing with one USBc > DP and one HDMI>DVI adapter>DVI cable.
 

macminitx

macrumors newbie
Dec 27, 2018
2
0
I just wandered in here from searching online. I am seeing the same issue with my HP 25es monitor connected via HDMI to my 2018 mini.
 

PlainBelliedSneetch

macrumors newbie
Oct 4, 2017
16
28
I have an acer K272HUL that would not wake up consistently when connected to my 2018 Mac mini’s HDMI port. It is working fine using the USB C port with an HDMI adaptor.
 

NomadMonad

macrumors newbie
Jan 7, 2019
2
0
I have an LG 24M38 connected via HDMI and I'm having the same issue. Static/black for a few seconds after sleep. I really really hope it's only a software bug as my last machine was a MacBook Pro early 2011 with the defective GPU issue.
 

Sarpanch

macrumors member
Jan 12, 2013
84
68
SoCal
I have a Dell U2518D connected to the HDMI port of a 2018 Mac Mini. No issues at all, whether it’s the Mini waking from short sleep (30-40mins) or deep sleep (>1 day). The monitor supports HDMI 2.0 and I am using the Amazon Basics HDMI 2 cable.
 

enri1357

macrumors member
Jul 31, 2016
65
30
The static you see if probably an issue with signaling issue, i suspect it is related to HDCP implementation. I saw the issue with my Samsung TV with a HDMI switches.

I see the same HDMI issues with HP. I also see a different Displayport issue with my LG. I am returning my Mac Mini
 

Martyimac

macrumors 68000
Aug 19, 2009
1,904
1,247
S. AZ.
My 2018 Mini i5 has the same static issue when plugged into HDMI. I found if I unplug the HDMI then plug it right back in, the static goes away. That tells me the handshake isn't doing it's thing correctly after sleep. Easy fix for me but do intend to get a USB-C cable at some point.
 

harriska2

macrumors 65816
Mar 16, 2011
1,266
639
Oregon
My 2018 Mini i5 has the same static issue when plugged into HDMI. I found if I unplug the HDMI then plug it right back in, the static goes away. That tells me the handshake isn't doing it's thing correctly after sleep. Easy fix for me but do intend to get a USB-C cable at some point.
That's weird. I use HDMI 2 cable with my Samsung 4k monitor to a connection box for the Samsung. I have 3 machines connected and no problems with monitor sleep or static.
 

Martyimac

macrumors 68000
Aug 19, 2009
1,904
1,247
S. AZ.
That's weird. I use HDMI 2 cable with my Samsung 4k monitor to a connection box for the Samsung. I have 3 machines connected and no problems with monitor sleep or static.
I should clarify, this is a HDMI to DVI-D cable.
Which would be better? USB-C to DVI or USB-C to DP? Those are my options if I want to not use HDMI output.
 

jacbernier

macrumors newbie
Jan 20, 2019
1
0
I'm having the static/snow screen display issue after awakening from sleep on my 2018 Mac mini. By static/snow, I mean the monitor display looks like the pattern an old TV using an antenna would display if it lost its signal. I returned my first 2018 mac mini because of this issue and the replacement 2018 Mac mini has the same issue. What I've learned about this issue is documented below. Apple tech support is not experienced with this issue, so, in the near term, it's up to the community of users to figure this out. Please add any knowledge or experience you have with this issue to this discussion.

My 2018 Mac mini set up:
OS version as of this post: Mojave 10.14.2. The mini is connected to two Samsung C24F390FHN monitors. One monitor is connected via an HDMI cable to the HDMI port on the mini and the HDMI port on the monitor. The other monitor is connected to a USB-C port on the mini and the HDMI port on the monitor.
Issue Observations:
  1. The static/snow display issue ONLY occurs when the mini awakes from being in sleep mode for a longer period of time. Clicking the Apple icon in the upper left corner and choosing "Sleep" and then waiting 4 minutes is long enough to cause the issue to appear.
  2. The issue ONLY occurs on the monitor connected to the HDMI port on the mini.
  3. The monitor connected via the USB-C port on the mini does NOT exhibit the snow/static display issue upon awakening from sleep mode.
  4. I isolated the issue to the HDMI port by switching how the two monitors were connected to the mini; either via HDMI or USB-C. Since the issue followed the HDMI port and not a specific monitor, this means either monitor is NOT the source of the issue. This issue is directly tied to the HDMI port on the mini.
  5. The issue fixes itself after less than a minute. The screen switches multiple times between displaying snow/static and a black screen and then eventually fixes itself.
  6. Disconnecting the HDMI cable from the mini or monitor and then reconnecting the HDMI cable also fixes the snow/static issue.
  7. Apple's tech support recommends three standard resets (PRAM, SMC and another acronym I don't recall), which do nothing for this issue. Don't waste your time performing these resets.
  8. Apple's tech support escalation process is ineffective for this issue. The third contact on my support case for this issue resulted in a Genius appointment that was a waste of time. The Genius stated that unless they can replicate the issue, the issue is likely specific to my computing environment. Rather than leave the mini at the genius bar for a few days, I chose to return the mini (it was only a few days old) thinking the issue was likely an anomaly only associated to the particular unit I had. That's not the case since my replacement mini has the exact same issue. My Apple tech support experience gave me the impression that since the 2018 Mac Mini is so new, Apple just doesn't have enough experience with this issue yet. Don't waste your time with a Genius appointment. You may even want to consider holding off on buying a 2018 Mac mini until this issue is figured out.
My next steps to get around this issue include:
  1. Try connecting both monitors via a USB-C port. As in, don't even use the HDMI port on the mini. This requires buying a new cable.
  2. If step 1 above doesn't work, then try using the HDMI port or a USB-C port on the mini to connect to the monitor via the VGA port or whatever other connection is available on the monitor besides the HDMI port. This requires buying a new HDMI to VGA cable or similar cable.
Updates as of 01-16-2019.
Both of my monitors are now connected via USB-C cables. Doing this replaced the snow issue after wake up from sleep with pure black screens being displayed for 20 seconds after awakening from sleep. Yes, there's an annoying 20 second wait EVERY time I awaken the mini from sleep. I also tried using an HDMI to VGA connection for one monitor. This didn't work at all. Don't waste your money trying this. The monitor connected via the HDMI to VGA cable would just constantly blink.

Having been through the Apple tech support process, Apple thinks the issue is a Samsung monitor issue (of course it can't be an Apple product issue...;)). Apple suggested everything from rearranging cables (possible interference) to trying new cables, which I tried. I then contacted Samsung tech support and described the issue, and yes, you guessed it; Samsung says it's an Apple product issue. Getting nowhere slowly. Anyway, I borrowed an LG monitor and.....yes, the same issues exist with the LG brand of monitor. I think the Monitor, Cables and Cable Arrangement can be eliminated as possible causes of the issues. The comments from others left below reporting the same issue using different monitor brands (Acer, LG, HP) adds more data points suggesting that the monitor is NOT the issue. I've reported this information back to Apple tech support and they seem to have gone silent. Hmmm? What's left to check? Perhaps the mini itself? To be continued...dah-dah-daaaaah!
[doublepost=1548036791][/doublepost]I've just had the static/snow screen after waking up my one month old MacMini 2018. Found this discussion right away. I have an LG monitor so that confirms that it's not a Samsung issue. I'm dismayed to see how Apple is (not) reacting.
 

RedGuest99

macrumors newbie
Original poster
Dec 20, 2018
10
11
[doublepost=1548036791][/doublepost]I've just had the static/snow screen after waking up my one month old MacMini 2018. Found this discussion right away. I have an LG monitor so that confirms that it's not a Samsung issue. I'm dismayed to see how Apple is (not) reacting.
My advice is to contact Apple tech support, but know that the process will unfold as noted below and don't buy any new cables or waste your time with a "Genius bar" appointment. You can use this post in your discussions.
1. Apple will start you off with a plain "advisor", who will suggest three or so different resets that won't work.
2. You will then be handed off to a "senior advisor", who will mention potential cable issues, connector issues and monitor issues specific to your "computing environment" as they call it. Don't waste your money buying new cables or anything else. New cables or connections won't resolve the issue.
3. The senior advisor will recommend a trip to an Apple genius bar. Don't waste your time doing this.
4. Most likely another senior advisor will be assigned to your issue and then ask you to install software on your mini that allows them to capture operational data at the very time the issue is taking place. I did this and sent the data back to Apple. I heard nothing for two weeks until I contacted Apple again only to learn that I was basically starting the process above over.
5. Be prepared to follow up and follow up and follow up again with Apple tech support. I think these hard issues somehow are difficult/demotivating for Apple employees to deal with. I'm still in this follow up phase on my 4th "senior advisor"....ugh
 
Last edited:

Martyimac

macrumors 68000
Aug 19, 2009
1,904
1,247
S. AZ.
Just an FYI, shifted to a USB-C to DP cable and haven't had a recurrence. But like most others, it only happened occasionally. The monitor is a Dell U2311H
 

FreakinEurekan

macrumors 68040
Sep 8, 2011
3,429
394
Eureka Springs, Arkansas
This is an irritating, but harmless, issue that's been plaguing the MacBook and MacBook Pro for probably a couple of years. I'm not surprised to see it on the Mini also. You'll get a second or two of static on wake from sleep, then... all is fine. Or sometimes it's a "mosaic" pattern instead, but still just for a couple of seconds.

You're welcome to contact AppleCare, take it to a Genius Bar, rattle chicken bones at it - whatever. The fact is, it's gonna do it sometimes, Apple engineering is aware of it, it doesn't cause a real problem, and they've decided it's not worth fixing at this point. Personally, I'd just ignore it.
 

brewmonkey

macrumors regular
Feb 17, 2016
201
137
This is an irritating, but harmless, issue that's been plaguing the MacBook and MacBook Pro for probably a couple of years. I'm not surprised to see it on the Mini also. You'll get a second or two of static on wake from sleep, then... all is fine. Or sometimes it's a "mosaic" pattern instead, but still just for a couple of seconds.

You're welcome to contact AppleCare, take it to a Genius Bar, rattle chicken bones at it - whatever. The fact is, it's gonna do it sometimes, Apple engineering is aware of it, it doesn't cause a real problem, and they've decided it's not worth fixing at this point. Personally, I'd just ignore it.
If the issue you're describing really only lasts a couple seconds, it is not the same issue discussed in this thread. On the mini I am working with, the static/snow does not go away until intervention occurs (replugging monitor, etc.).
 
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Jimrob

macrumors newbie
Jan 22, 2019
1
0
AZ
I am also having the same snow issue with my 2018 Mac mini i7. Snow will not go away until I unplug HDMI from the back of the mini and plug it back in. My old 2012 i7 mini also had the same issue. Monitor is a Asus VG248.
 
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