Constant Freezing and Restarts - iMac (Retina 5K, 27-inch, Late 2014)

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Constant Freezing and Restarts - iMac (Retina 5K, 27-inch, Late 2014)

I have an iMac that is essentially unusable due to constant freezing and restarts. The frequency can be multiple times per hour and it seems to happen more often when video or images are being displayed in a browser window. I am currently running macOS Sierra, but experienced the issue under El Capitan and Yosemite when they were installed. It feels as though the issue has increased in frequency over the past year, but I did not keep count. The frequency started to occur enough that I gave up trying to live with it and decided to contact support. I was hopeful that Sierra would fix the issue, but that was not the case.

As you'll see below, I have contacted support and dropped the computer off at the Apple Store, but Apple states there is no problem. After doing my own troubleshooting based on research in various forums, I am posting this as my last gasp hope that someone has a silver bullet that fixes this crippling issue. If I can not find a fix, then my only recourse is to contact Apple to return the computer for a full refund, or get them agree to replace the computer with a new, working model. Curious if anyone has had success with this approach for this model of iMac after experiencing similar issues.

Thank you in advanced for your assistance. I am open to all suggestions at this point. If you need more information please let me know and I’ll do my best to provide it as quickly as possible.

tomantrim

Behavior and Symptoms Experienced:

Computer will freeze and all windows and menus become unresponsive. Most of the time I can still move the cursor around on the screen, but that is the only aspect of the system that seems to work. If there is music/audio playing it will continue to play uninterrupted. After 1-3 minutes the windows/menus become responsive again and I can continue to use the computer.
Computer will freeze as described above, but never becomes responsive again and eventually restarts to the login screen. The user account has been logged out in this case. After I login again, the computer seems to work normally again until the freezing occurs again.
Computer will freeze as described above, but never becomes responsive again and eventually goes to a black screen and the computer restarts displaying the Apple logo and progress bar.
Periodically when the computer freezes and prior to restarting the fan can be heard spinning up and becomes very loud. In this case, it usually goes to the black screen described above before rebooting.
In some cases when the computer freezes portions of the screen turn bright red and the windows appear to break apart and are displayed in a fragmented fashion. Today, I was able to capture an example of this with my iPhone in the attached picture. There are two Safari browser windows in the picture attached and the bright red displayed was not part of the original web pages.

Troubleshooting Completed To Date:

Apple Support:

Contacted Apple Support last weekend and spent ~4 hours with two different reps via chat. During the chat session I mentioned I had read that some iMac's have had a problem with the graphics card and needed to have them replaced. Apple Support stated that most often it is just a software issue. They had me perform the following troubleshooting steps.

SMC Reset

NVRAM/PRAM Reset

Logged into my user account

Used computer for ~5 minutes

Experienced the issue

Created new TEST account

Logged into the TEST account

Used computer for ~5 minutes

Experienced the issue

Booted into OS X Recovery via Command-R

Ran First Aid on Macintosh HD

First Aid completed without any errors

Logged into my user account

Used computer for ~5 minutes

Experienced the issue

Booted into OS X Recovery

Selected "Reinstall MacOS"

While waiting received the error, "macOS Sierra failed to download. Use the Purchases page to try again"

Exited Reinstall and started new Reinstall attempt

Progress bar did not move after several minutes. No error message this time.

Rebooted iMac and went back to OS X Recovery

Selected "Disk Utility"

Selected "Macintosh HD" and selected "Erase" with "Macintosh OS Extended (Journaled)" as the option.

Macintosh HD erased and Disk Utility stated "Operation Successful"

Selected "Reinstall MacOS"

Reinstall completed successfully and rebooted

Created new TEST account

Logged into the TEST account

I did not experience the issue immediately, so Apple Support asked that I monitor the iMac for 24 hours before restoring any backups

Used the computer in the new TEST account for about 1 hour

Experienced the issue

Contacted Apple Support again

Had me perform Apple Diagnostics via holding down D key while rebooting

Asked me to do "Extended Test" if available as an option

Computer did not present any options and just began running the diagnostic test

After about 5 minutes it came back with the following result, "No issues found. Reference Code: ADP000"

Next, had me restart into OS X Recovery mode via Command-R

Selected "Disk Utility"

Selected "Macintosh HD"

Apple Support had me take a picture of the screen and send it to them (included in Dropbox link below)

They set up an appointment at the local Apple Store for this past Wednesday

Apple Store:

Dropped off the computer at the Apple Store, explained all the issues I was experiencing.

While I was there, they ran a 5 minute diagnostic on the iMac and no problems were found

Below is the Problem Description/Diagnosis captured by the Apple Store when I dropped it off.

Problem Description/Diagnosis

Issue: Customer states that machine will freeze and he won't be able to do anything. He says when it freezes it just will not respond to the clicks when clicking on anything. We don't get a colored spinning wheel he states when that happens.

Steps to Reproduce: Ran Mac Resource Inspector and found no issues.

I booted to his test user account that was created after a reinstall that was performed with phone support, could not replicate issues.

Cosmetic Condition: No damage to display or enclosure.

Proposed Resolution: Check in for full ASD testing.

Estimated Turn Around Time: We'll call you within 48 hours

Mac OS Version: Unknown

Hard Drive Size: 3000

Memory Size: 32768

iLife Version: Unknown

They kept the iMac to do their testing

I received a call on Friday from the Apple Store and they stated that the 24 hour diagnostic did not find any problems. I explained I was surprised by this due to the frequency of the issue. The Apple Store stated the freezing was probably caused by my Internet connection. Note we have four other MacOS computers in our house, including an older iMac and none of them experience this same issue.

They stated they would do a "deep" reinstall that only they can do. This was to make sure everything possible is removed and it is restored to the original state.

I picked up the computer and brought it back home and booted it up last night

The computer had macOS Sierra installed, but did not have an account set up

Created new TEST account

Logged into the TEST account

Used computer for ~10 minutes

Experienced the issue

I continued to use the computer and experienced the issue multiple times

Additional Troubleshooting Performed Based On My Own Research:

Below is all the troubleshooting steps I completed after bringing the iMac home from the Apple Store. The steps below are cumulative in that each change I made remained in place for the subsequent steps, so with each step more variables have been removed from the environment to hopefully narrow the possible causes of the issue. In all of the cases below, the only software installed on the iMac is what comes standard with the OS, except where noted.

Based on my experiments last night I developed a test that has been successful in causing the freezing issue to occur, documented below. This is the test I ran after each troubleshooting change documented below.

The Test

Open Safari browser window

Note Safari is the only application running during this test

Go to youtube.com

Play a music video, I used "Coldplay - The Scientist" in each test, so it was consistent from test to test. Also, it was first video I ran across that I could stand listening to over and over.

While the music video is playing, open a separate browser window in Safari

Go to buzzfeed.com

Click on "Videos"

Begin slowly scrolling down the page, pause until the first video begins playing

Let the video play for a few seconds and then scroll down to the next video until it starts playing

Repeat this process for each video letting each one play a few seconds until the iMac freezes

In most cases the iMac freezes before the Coldplay - The Scientist video finishes which is 4:26 long. Occasionally it will start the next Coldplay song, but this is rare, and I almost always experienced the freezing before the second song completed.

Clean Reinstall: Yosemite 10.10.5

Since I continued to experience the issue after picking up the computer from the Apple Store, I decided to do another reinstall. First I did an SMC Reset and NVRAM/PRAM reset. I booted into OS X Recovery and erased the hard drive, then reinstalled the OS. Yosemite was the only OS option available, I assume Yosemite was the only option due to the "deep" reinstall performed at the Apple Store.
After Yosemite was installed, I created a TEST account and checked for any software updates. There were several updates which I installed. Since I hadn't run Yosemite for a while, I took the opportunity to see if I would experience the freezing under this older OS. Note, I did not install any other software at this point. The only software installed is what is standard with Mac OS.
With Yosemite installed and fully updated, I performed "The Test"
Experienced the issue

Clean Reinstall: macOS Sierra 12.0

With the confirmation the issue occurred in Yosemite I downloaded macOS Sierra from the App Store and installed it
Just to be extra cautious and to insure the issue was not caused by some legacy Yosemite software installs, I then rebooted into OS X Recovery, erased the hard drive and did a clean install of MacOS Sierra
With macOS Sierra installed I ran "The Test"
Experienced the issue

Disconnect Third-Party Peripherals

To confirm that the issue wasn’t caused by third-party peripherals plugged into the iMac, I unplugged the following peripherals:
- Fujitsu ScanSnap S1500M directly connected via USB cable to back of iMac
- Demo LabelWriter Duo directly connected via USB cable to back of iMac
Klipsch external speakers directly connected via audio cable into headphone port on back of iMac
The following peripherals remain connected to the iMac:
Apple USB extended keyboard
Amazon Basics USB mouse with two buttons and scroll wheel
After unplugging the above peripherals, I rebooted the computer and I ran "The Test"
Experienced the issue

Disconnect Apple AirPort Extreme AC with External Time Machine Back Up Disk & Disable WIFI:

Early on I had developed my own theory that Time Machine backups and the periodic disk access might be causing the iMac to freeze. This was not based on anything I found in my research, just a hunch. My Time Machine back up disk is connected to an AirPort Extreme AC and my iMac is plugged into the Airport directly via ethernet cable.
Now, after all the reinstalls I had not turned on Time Machine, but just in case the disk access by other Macs on our network was causing the freezing issue on the iMac, I bypassed the Airport entirely and plugged the iMac ethernet cable directly into my cable provider's router. I also disabled WIFI on the iMac in case that was causing any issues.
For the record my provider is AT&T UVerse and Ariss AVG589 is my modem
After eliminating the AirPort Extreme and Time Machine disk from the picture, I ran "The Test"
Experienced the issue

Disable Bluetooth in System Preferences

I read that some eliminated the issue by disabling Bluetooth. I disabled this in System Preferences, closed Safari, restarted the computer and ran "The Test"
Experienced the issue

Disable "Allow WebGL" in Safari Preferences

I read that disabling “Allow WebGL” in Safari fixed this issue for some people. I disabled this setting, closed Safari, restarted the computer and ran "The Test"
Experienced the issue
I will say the iMac ran a little bit longer under this condition, but maybe I just got lucky

Install Chrome with “Use Hardware Acceleration when available” Disabled

There were many suggestions on using alternate browsers with Chrome being the one most mentioned. In some posts they suggested turning off “Use Hardware Acceleration when available”
I installed Chrome, turned off this setting, restarted the computer and ran "The Test"
Experienced the issue
While it took a little longer for the iMac to freeze with Chrome as the browser, maybe three Coldplay songs vs the usual one it did eventually occur

Other Notes And Observations:

As mentioned earlier in the post, the screen image does display strange artifacts during some of the freeze ups. Screenshot attached and another one in the dropbox folder linked below.
After one of the freezes and restarts I captured logs from the console app. There were 16 entries titled with the following naming schema, “Kernel_YYYY_MM_DD_TTTTTTTT_TESTs-iMac.gpuRestart”. These logs are also in the linked Dropbox folder. These occurred during the same restart that I captured the screenshots from.
As I browsed the logs, there multiple mentions of a “GPU Restart” immediately prior to the crash and restart. I tried to capture as many of the logs that looked to be relevant to this issue and included them in the Dropbox folder.
After one restart I received a pop up from the system wanting to send information to Apple regarding a, “Sleep Wake Failure”. I captured the details and included in the Dropbox folder.
Below is a run from EtreCheck since that seemed to be a common request in other posts.

Dropbox link with log files and screenshots:

https://www.dropbox.com/sh/prvo9gpd0dathwx/AAAft2u06FGskqQMDkZ1lKW0a?dl=0

EtreCheck Results:

EtreCheck version: 3.0.6 (315)

Report generated 2016-10-15 12:19:08

Download EtreCheck from https://etrecheck.com

Runtime 1:18

Performance: Excellent

Click the [Support] links for help with non-Apple products.

Click the [Details] links for more information about that line.

Problem: Computer is restarting

Hardware Information:ⓘ

iMac (Retina 5K, 27-inch, Late 2014)

[Technical Specifications] - [User Guide] - [Warranty & Service]

iMac - model: iMac15,1

1 4 GHz Intel Core i7 CPU: 4-core

32 GB RAM Upgradeable - [Instructions]

BANK 0/DIMM0

8 GB DDR3 1600 MHz ok

BANK 1/DIMM0

8 GB DDR3 1600 MHz ok

BANK 0/DIMM1

8 GB DDR3 1600 MHz ok

BANK 1/DIMM1

8 GB DDR3 1600 MHz ok

Bluetooth: Good - Handoff/Airdrop2 supported

Wireless: en1: 802.11 a/b/g/n/ac

Video Information:ⓘ

AMD Radeon R9 M295X - VRAM: 4096 MB

iMac 5120 x 2880

System Software:ⓘ

macOS Sierra 10.12 (16A323) - Time since boot: less than an hour

Disk Information:ⓘ

APPLE SSD SM0128G disk0 : (121.33 GB) (Solid State - TRIM: Yes)

EFI (disk0s1) <not mounted> : 210 MB

Boot OS X (disk0s3) <not mounted> : 134 MB

Macintosh HD (disk2) / [Startup]: 3.11 TB (3.10 TB free)

Core Storage: disk0s2 120.99 GB Online

Core Storage: disk1s2 3.00 TB Online

APPLE HDD ST3000DM001 disk1 : (3 TB) (Rotational)

EFI (disk1s1) <not mounted> : 210 MB

Recovery HD (disk1s3) <not mounted> [Recovery]: 650 MB

Macintosh HD (disk2) / [Startup]: 3.11 TB (3.10 TB free)

Core Storage: disk0s2 120.99 GB Online

Core Storage: disk1s2 3.00 TB Online

USB Information:ⓘ

Apple Inc. BRCM20702 Hub

Apple Inc. Bluetooth USB Host Controller

Apple Inc. FaceTime HD Camera (Built-in)

Apple, Inc. Keyboard Hub

Apple Inc. Apple Keyboard

Thunderbolt Information:ⓘ

Apple Inc. thunderbolt_bus

Gatekeeper:ⓘ

Mac App Store and identified developers

System Launch Agents:ⓘ

[not loaded] 5 Apple tasks

[loaded] 182 Apple tasks

[running] 84 Apple tasks

System Launch Daemons:ⓘ

[not loaded] 42 Apple tasks

[loaded] 166 Apple tasks

[running] 94 Apple tasks

User Login Items:ⓘ

iTunesHelper Application (/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)

Internet Plug-ins:ⓘ

QuickTime Plugin: 7.7.3 (2016-09-13)

3rd Party Preference Panes:ⓘ

None

Time Machine:ⓘ

Time Machine not configured!

Top Processes by CPU:ⓘ

21% assistant_service

3% WindowServer

3% fontd

0% assistantd

0% kernel_task

Top Processes by Memory:ⓘ

1.35 GB kernel_task

98 MB Dock

66 MB softwareupdated

66 MB mds_stores

66 MB Finder

Virtual Memory Information:ⓘ

28.00 GB Free RAM

3.81 GB Used RAM (1.31 GB Cached)

0 B Swap Used

Diagnostics Information:ⓘ

Oct 15, 2016, 12:05:11 PM Self test - passed

iMac (Retina 5K, 27-inch, Late 2014), macOS Sierra (10.12)

Posted on Oct 15, 2016 3:07 PM

Reply

Answer 1

Feb 22, 2017 5:26 PM in response to tomantrim

I have a problem that seems related - am buoyed by your description. My Late 2013 iMac/Sierra started misbehaving a few weeks ago - the system starts up as expected, but the cursor is ignored, altho it can be driven by (either of) two available mice. Clicking does not do anything, but the keyboard (long, USB) does function appropriately when it gets the chance. (I also had a black-screen problem a few weeks ago, cleared by reinstalling the system from Recovery.)

Rebooting is the only way I've found to get the system to respond to mouse clicks. Initially a reboot cleared the problem, but recently it is less likely to do so without repeated attempts.

A boot into Safe Mode cleared the problem - until restarting.

I have done hardware check (OK) and attempted to boot into Recovery Mode but the latter failed to recognise the local WiFi connection, so I was unable to reach recovery mode.

A boot from a backup system copy also produced the problem.

I'll recommence from scratch and then approach Apple. It seems like a hardware or firmware problem to me.

Reply

Answer 2

tomantrim Author

Level 1

10 points

Oct 17, 2016 5:40 AM in response to tomantrim

Spent some time talking to an Apple tier 2 advisor this week. He provided a capture program to grab logs and I uploaded them to Apple. A tier 3 advisor (think that is what he called them) will look at the logs to determine if there are any hardware issues.

Since there were no responses. I'm taking down the dropbox link.

tomantrim

Reply

Answer 3

Nov 8, 2016 2:28 PM in response to tomantrim

I Have a late iMac 5k Retina and it has the same issues. The problem seems to be the graphics card or driver. I currently run OS Sierra in Safe Mode and apparently it crashes far less. Considering the error logs and phenomena you have it is a graphics problem. Google on iMAC 5k Retina late 2014 and you will see that graphics is the problem.

Our only hope is that they just released a MacBook Pro with touch bar with 5k capabilities and I hope that this will force Apple to look deeper into these problems with 5k.

Nevertheless, Apple has disappointed me very badly wit this product I have been an Apple fan and bought many products from them. This iMac was, considering the cost, a once in my lifetime purchase and I hoped to do great things with this. But all I am doing is dealing with all these stupid resets and get nothing done. Hope that help will finally come.

Reply

Answer 4

rkaufmann87

Level 10

147,032 points

Nov 8, 2016 2:35 PM in response to tomantrim

You only posted part of the EtreCheck report, the most important aspect (what is installed) was left off. Please re-run an EtreCheck report and post it in it's entirety as a reply to this message.

Reply

Answer 5

Nov 20, 2016 2:32 PM in response to tomantrim

Hi, any news, I took my IMac to the apple repair shop, the situation was that things got worse. I was not able to open 2 apps simultaneously. Not even system settings. Situation did not improve even after making a clean reinstall of Yosemite as it initially came installed with that. Apple Support was great I must say, I just hope they find the issue in the apple repair shop.

Reply

Answer 6

Dec 4, 2016 9:04 AM in response to RudolfApple

Update: The logic board of the iMac got replace, service center expects that the graphics section of the board was weak and got it's final blow when processing the Photos library (GPS data and face recognition for multiple thousands of photo's) after installation of MacOS Sierra. During that process I did observe processor usage of over 170% for extended time. Seems to make sense to me, the iMac now runs for 7 days without any issue. Thanks to the Apple support team and to the service centre that repaired the iMac.

Hope this is my last post in this thread / monologue.

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Constant Freezing and Restarts - iMac (Retina 5K, 27-inch, Late 2014)