Weird Screen Flickering

[Phail]

Dear community,

please help me, I have a really strange problem with my MacBook Pro A1502 (early 2015 13 "). I bought this used MacBook a few months ago. Everything worked fine, no problems. A few days ago I got a song about iTunes added and suddenly the picture started to flicker and didn't want to stop, you can see on the pictures how this is expressed on the screen. It occurs during the boot process, approximately when the bar has reached halfway. The only thing that flickers then is the Apple Logo and the loading bar.

The flickering does not occur if:

My MacBook is connected to an external monitor via HDMI or Thunderbolt 2 (no flickering on both screens, everything is normal)

The MacBook is booted into Safe Mode

It's less common when CleanMyMac is running in the background (I´ve installed the program after the first time the screen has flickered)

When a video is running (YouTube, Netflix; As soon as the video starts, it flickers 3-4 times and then stops; If it flickers in full screen, it's often gray/white squares as can be seen in the last picture)

It is also not visible on screenshots or screen recordings

What I've tried so far:

MacOS Montery 12.1. reinstalled

MacOS Montery 12.1 Cleaninstall

MacOS Catalina Cleaninstall

MacOS Mojave Cleaninstall

changed the LVDS cable

PRAM, VRAM, SMC reset

Please help me! Does anyone have any idea what to try? It seems like some of the flicker is related to keystrokes as well, but it also happens when I'm not typing on the keyboard.

Thanks in advance!

Greets from Austria and stay safe

Phillip

 

[pigoo3]

Hello Phillip...welcome to Mac-Forums.

The flickering does not occur if:

My MacBook is connected to an external monitor via HDMI or Thunderbolt 2 (no flickering on both screens, everything is normal)

This is good news...since this very likely means the logic board is fine (the most expensive part of a most computers).

When you say "both screens"...are you saying both the MacBook Pro display & a single connected external display? Just want to be sure.

It's less common when CleanMyMac is running in the background (I´ve installed the program after the first time the screen has flickered)

When a video is running (YouTube, Netflix; As soon as the video starts, it flickers 3-4 times and then stops; If it flickers in full screen, it's often gray/white squares as can be seen in the last picture)

Is this happening when the MacBook Pro is not connected to an external monitor?

What I've tried so far:

MacOS Montery 12.1. reinstalled

MacOS Montery 12.1 Cleaninstall

MacOS Catalina Cleaninstall

MacOS Mojave Cleaninstall

changed the LVDS cable

PRAM, VRAM, SMC reset

Please help me! Does anyone have any idea what to try? It seems like some of the flicker is related to keystrokes as well, but it also happens when I'm not typing on the keyboard.

Looks like you've done quite a bit of troubleshooting. I know you mentioned doing "clean installs" of the macOS.

What I prefer to do when there's a problem like this...I like to narrow things down to...is it a hardware or software/macOS issue. The most effective way I like to do this is...use a freshly formatted external hard drive or external SSD...then do a 100% fresh install of the macOS on this external drive. Then boot the computer from this external drive.

If the problems remain...then you have a hardware issue. If the problems disappear...then it's a software or macOS issue on the "main" internal drive.

HTH,

Nick

p.s. Can you please explain what the images in the original post relate to? They do not look like screen flickering to me...they look like something totally different.

 

[Phail]

Hi Nick thanks for taking the time to address my issue!

This is good news...since this very likely means the logic board is fine (the most expensive part of a most computers).

When you say "both screens"...are you saying both the MacBook Pro display & a single connected external display?

Exactly both screens work without problems and it's as if there was never a problem.

Is this happening when the MacBook Pro is not connected to an external monitor?

Yes! That's the next problem that I don't understand. I watched a 45 minute video today without having an external monitor connected and it didn't flicker. it doesn't matter if it's running full screen or not. As long as the video is playing, it doesn't flicker.

Looks like you've done quite a bit of troubleshooting. I know you mentioned doing "clean installs" of the macOS.

What I prefer to do when there's a problem like this...I like to narrow things down to...is it a hardware or software/macOS issue. The most effective way I like to do this is...use a freshly formatted external hard drive or external SSD...then do a 100% fresh install of the macOS on this external drive. Then boot the computer from this external drive.

If the problems remain...then you have a hardware issue. If the problems disappear...then it's a software or macOS issue on the "main" internal drive.

I created a bootable USB stick (one each with Montery, Catalina and Mojave), wiped my hard drive completely and then booted to the completely clean hard drive. But as you say, I could try the whole thing again with an external drive!

p.s. Can you please explain what the images in the original post relate to? They do not look like screen flickering to me...they look like something totally different.

In the pictures you can see what I mean by flickering. The patterns and colors are often different, but I have seen certain patterns more than once. Sometimes they are only there for a very short time and sometimes for several seconds. In the last picture you can see what it looks like at the beginning, as soon as I go into full screen mode on a YouTube video. This is just a short flicker and it flickers 4-5 times and then it stops until I pause or close the youtube video. I hope I was able to explain it to you in a way that was understandable. I can also record a video and put it on Youtube where you can see the flickering.

Thank you!

Phil

 

[Rod]

I think you have pretty much eliminated the software as the cause of the problem, if I understand you correctly it only happens with the built in display which means that is the culprit.
There are a number of things that can go wrong with a screen such as a damaged cable, corroded terminals, dead pixels etc and replacement is usually the only answer but have a look at iFixit eg. My MBP retina screen is flickering, what can I do? - MacBook Pro 13" Retina Display Late 2013
They have a host of problem solving tips and step by step guides to hardware replacement if thats what it comes down to.

 

[Phail]

I was almost convinced that it must be a hardware problem but today I installed Windows 10 using Bootcamp. The Flickering does not occur on Windows 10. So I think a hardware problem can be ruled out now... The error must be so deep in the MacOS that not even a cleaninstall solves the problem. I don't even know if that's possible, but what else is it supposed to be?
If you have any other ideas please let me know.

Greets
Phillip

 

[pigoo3]

* Given this issue only happens when ONLY using the MacBook Pro's built-in display (no external monitor attached).
* Given there is no issue when an external monitor is connected.
* Given the issue remains when the internal drive is wiped & a fresh version of the macOS is installed.

About the only thing left is a hardware issue that only affects the MacBook Pro built in display. You did mention replacing the LVDS cable (not sure if the old one was bad). Assuming the replacement LVDS cable was installed properly...I guess it's possible the new cable could have an issue.

Regarding the images included in post #1. My first thought would have been a GPU issue. But since it was mentioned when an external display is connected...all is fine. If the GPU was bad/going bad...the issues would be on the external display as well.

Seems to me the best place to focus is on something internal (hardware)...and something to do with the internal display.

Nick

 

[MacInWin]

Images ending in 33 and 54 are very strangely orderly. A GPU failure, or a cable failure, is unlikely to produce orderliness like that. I don't really have a good solution or suggestion for you other that try to take a true screenshot (not a picture of the screen, a screenshot from the keys) when the images appear to see if it's in the GPU or just the screen. If GPU, the screenshot will show the same as your photographs of the screen. If just the screen or cable, the screenshot will be fine, but the screen will have anomalies.

 

[pigoo3]

Images ending in 33 and 54 are very strangely orderly. A GPU failure, or a cable failure, is unlikely to produce orderliness like that.

This was my inital thoughts as well. The images don't look like "display flickering"...and as you said Jake...they look way too "ordered". GPU related issues usually are more dis-ordered, random, or chaotic.

I also don't think screen flickering can be properly communicated via screenshots...since display flickering happens so quickly...would be difficult to capture via a screenshot (video a much better way to capture the flickering).

Given the orderliness of the images...connected external displays work fine (internal display works some of the time)...fresh macOS installs don't solve things. I'm wondering if the firmware has been messed with in some way...or if something was done with Terminal to alter how the computer operates.

Nick

 

[MacInWin]

Given the orderliness of the images...connected external displays work fine (internal display works some of the time)...fresh macOS installs don't solve things. I'm wondering if the firmware has been messed with in some way...or if something was done with Terminal to alter how the computer operates.

Yeah, something strange is going on with this. My thinking on the screenshot is that if the images appear for a few seconds (which apparently they do, he took pictures of them), then a screenshot will show if it's the GPU or something in the display process.

 

[Phail]

Hey guys, thanks for your input, I really appreciate it!

I already wrote in my post #1 that the flickering is not visible on screenshots or screen recordings. I've already tried that.

@pigoo3 : I swapped the LVDS cable, thinking that would solve the flickering problem. However, I had the same problem with the new cable and then I installed the old one again.

It is completely incomprehensible to me that the problem does not occur on Windows 10. I'm typing this message on my Mac running Windows 10 without having an external monitor connected. No flickering. Not a single time.

I mean, that completely rules out a hardware defect, doesn't it?

I haven't changed anything in the terminal. But my guess is also that something is wrong with the deepest macOS firmware.
Is there a level above the cleaninstall?

I've spent many hours researching this problem. The day before yesterday I found a user who reported exactly the same problem with the same model. So at least it's not the first time.

Just let me know if you need more info, pictures or videos.

greets
Philip

 

[MacInWin]

I mean, that completely rules out a hardware defect, doesn't it?

No, it does not. There is no guarantee that Win10 uses the full capabilities of the GPU the way macOS does. The problem could be in a portion of the GPU that Win 10 never activates.

I haven't changed anything in the terminal. But my guess is also that something is wrong with the deepest macOS firmware.
Is there a level above the cleaninstall?

What do you mean? What is "above the cleaninstall?" The installer for macOS checks for the required firmware for that version and if needed, installs it along with the OS. As for the idea of something being worn with the "deepest macOS firmware," if that were true there would be thousands of folks in the same situation. There is not, so it's very unlikely to be a firmware issue.

Where is this "other user" you found? It would be interesting to see what he/she has tried.

A few days ago I got a song about iTunes added

You mentioned this in your first post. Maybe the song track contained malware? Have you tried running DetectX Swift or Intego VirusBarrier Scanner to check for malware?

Some of the 2015 models, as I recall, had a faulty GPU that was the subject of an extended warranty from Apple. Sadly, that has expired now. But one of the workarounds to get a faulty GPU to work, at least partially, was to disable some more advanced functions in the GPU and use lower-performing parts of the GPU to allow the system to continue to function at any level. It could well be that your external monitors force that restrictive behavior (I'm guessing here, don't know anything about your monitors or setup). Ditto for Win10, as i said before.

 

[Phail]

No, it does not. There is no guarantee that Win10 uses the full capabilities of the GPU the way macOS does. The problem could be in a portion of the GPU that Win 10 never activates.

Ok that sounds logical. But a defective GPU is more likely to be ruled out by the fact that, firstly, the flickering cannot be seen on screenshots and, secondly, it does not exist as soon as a second monitor is connected. Or am I wrong?

What do you mean? What is "above the cleaninstall?" The installer for macOS checks for the required firmware for that version and if needed, installs it along with the OS. As for the idea of something being worn with the "deepest macOS firmware," if that were true there would be thousands of folks in the same situation. There is not, so it's very unlikely to be a firmware issue.

I was just wondering if, despite the clean install, some of the original possibly broken firmware remains on the macbook, which in turn causes the flickering problem. But the only thing that remains untouched with a cleaninstall is the base system and I think that has nothing to do with this problem, does it?

Where is this "other user" you found? It would be interesting to see what he/she has tried.

That was in a German-speaking forum. Only suggested solutions were mentioned that I have already tried and the problem remained unsolved. However, I left a comment and asked the user if he had found a solution to the problem in the meantime (the post was from 2019).

You mentioned this in your first post. Maybe the song track contained malware? Have you tried running DetectX Swift or Intego VirusBarrier Scanner to check for malware?

No, that's unlikely and I've already scanned the Mac with antivirus software. But I will still download the programs you mentioned and just try it again.

I may have forgotten to mention something else. The previous owner of this Macbook reported the same problem. He even uploaded a video of the problem he was experiencing to youtube (the video:

) . The macbook was then idle for some time until I bought it. I haven't had the problem for 4 weeks. Then I added the song to itunes (just an audio file from my band) and it started.

Some of the 2015 models, as I recall, had a faulty GPU that was the subject of an extended warranty from Apple. Sadly, that has expired now. But one of the workarounds to get a faulty GPU to work, at least partially, was to disable some more advanced functions in the GPU and use lower-performing parts of the GPU to allow the system to continue to function at any level.

I think it's not a problem caused by performance. I tried minecraft because it's the only game on my macbook. I loaded a complex world and during the loading process, it still flickered extremely and the fans gave full throttle. Once I was in the World I increased the view range to put more strain on the MacBook, but there was no flickering. That brings me back to the point: the picture doesn't flicker when there are moving pictures on the screen. But actually I have no idea. That's why I'm writing in a forum. To hear the opinion of people like you who certainly have more knowledge in this area than I do. ;-)

It could well be that your external monitors force that restrictive behavior (I'm guessing here, don't know anything about your monitors or setup). Ditto for Win10, as i said before.

My setup is simple. Only an HD monitor and my macbook. I only use it for light work (for example word).

 

[IWT]

@Phail

The thing that struck me about the video you kindly shared was that the flickering was closely related to the movement of the cursor.

If this is so - and I am by no means certain - would this help our senior colleagues to suggest a cause/solution?

Ian

 

[Rod]

It might be time to consider trading it in on a new one. You have obviously spent a lot of time on this process of elimination but when it comes down to replacing screens or motherboards to elimate them the cost becomes prohibitive. If you use it as a trade in you will not be passing on the problem like the previous owner did.

 

[Phail]

The thing that struck me about the video you kindly shared was that the flickering was closely related to the movement of the cursor.

If this is so - and I am by no means certain - would this help our senior colleagues to suggest a cause/solution?

Ian

I guess it's the same principle when moving the mouse as when a video is played. As soon as something moves, the flickering stops.
I will also install Linux, since it's partly similar to MacOS if I'm not mistaken. I'm curious if it doesn't occur there (like in Win10).

greets
Phillip

 

[Phail]

It might be time to consider trading it in on a new one. You have obviously spent a lot of time on this process of elimination but when it comes down to replacing screens or motherboards to elimate them the cost becomes prohibitive. If you use it as a trade in you will not be passing on the problem like the previous owner did.

Yes I may do that after some time, but not yet. The problem does not make the laptop unusable. If I can not connect it to an external monitor, I just use it under Win10 (or Linux if the flickering does not occur there either).
I also ordered an HDMI dummy that tells the laptop that an external monitor is connected. It will arrive tomorrow and if it works, I'll even be mobile again with macOS. On the side I still want to solve the problem. But as you say, I will now no longer invest a lot of money in the laptop.

greets
Phillip

 

[pigoo3]

Thanks much for the video Phillip. If this is exactly the sort of flickering you're seeing...and it ONLY happens when not connected to an external monitor...very very unusual.

* Looking at the video & the flickering...I think most folks would say this is absolutely a hardware issue. But then everything seems to work fine when an external display is attached.

* You mentioned the flickering does not happen if running Windows 10 (I'm assuming no external monitor). This would seem to rule out a software issue.

If we ignore for the moment the external monitor details. The computer works fine on it's own with Windows 10...but flickers when running the macOS (again no external display attached).

The one VERY important detail mentioned in post #1 was...the flickering does not occur when booted into Safe Mode.

Since many many other things have been tried & tested...and since the flickering doesn't occur when in Safe Mode...I would give what I suggested in post #2 a try. Take a freshly formatted external drive (hard drive or SSD)...install a 100% fresh copy of the macOS on it (Mojave or Catalina)...then boot the computer from this external drive.

To be even more conservative/careful...don't use the macOS installers you have (just in case there's an issue with them)...download fresh installers (hopefully from Apple). This way nothing that has already been tried is replicated (everything is a new test)...including not using the same macOS installers.

I know this is a bit of work. But given what you've done so far...a little bit more may be worth it to get to the bottom of this problem.

Nick

 

[Phail]

Thanks much for the video Phillip. If this is exactly the sort of flickering you're seeing...and it ONLY happens when not connected to an external monitor...very very unusual.

Yeah that's pretty much the flickering I'm experiencing. Sometimes it appears in different colors or patterns, as seen in my pictures.

* Looking at the video & the flickering...I think most folks would say this is absolutely a hardware issue. But then everything seems to work fine when an external display is attached.

The problem has never occurred with the external monitor connected.

* You mentioned the flickering does not happen if running Windows 10 (I'm assuming no external monitor). This would seem to rule out a software issue.

You are right. No flickering in Win10. Even when the external monitor is disconnected. Simply put, this problem does not exist in Win10.

If we ignore for the moment the external monitor details. The computer works fine on it's own with Windows 10...but flickers when running the macOS (again no external display attached).

Exactly.

The one VERY important detail mentioned in post #1 was...the flickering does not occur when booted into Safe Mode.

Since many many other things have been tried & tested...and since the flickering doesn't occur when in Safe Mode...I would give what I suggested in post #2 a try. Take a freshly formatted external drive (hard drive or SSD)...install a 100% fresh copy of the macOS on it (Mojave or Catalina)...then boot the computer from this external drive.

I will try that today! But I think the previous owner has tried this before and it did not help. However, maybe not with Mojave or Catalina.

I know this is a bit of work. But given what you've done so far...a little bit more may be worth it to get to the bottom of this problem.

The more time I invest, the greater the desire to find the cause of the problem. The only problem is that the possible reasons for the problem become fewer and fewer.

Thx again for your message @pigoo3!

Greets

Phillip

 

[pigoo3]

I will try that today! But I think the previous owner has tried this before and it did not help. However, maybe not with Mojave or Catalina.

Good deal. I'm suggesting 100% clean install of Mojave or Catalina on the external drive...mostly because they should be pretty stable.

Good luck. Hopefully we discover something positive.

Nick

 

[Phail]

Good deal. I'm suggesting 100% clean install of Mojave or Catalina on the external drive...mostly because they should be pretty stable.

Good luck. Hopefully we discover something positive.

Nick

Hi Nick,

unfortunately no success.
I installed Mojave on a freshly formatted external SSD and macOS ElCapitan on another freshly formatted original Apple internal SSD. With both software versions the flickering still occurred. The only other thing I could try is to install macOS from another MacBook to the external SSD and then boot it on mine. But I can't imagine that makes a difference.
I could also try installing Linux. But even if the flickering doesn't occur with Linux, I don't know what else could be done to stop it in macOS.

Feel free to let me know if you have any other ideas!

Thanks in advance

Phillip