Screen freezes for a few seconds

The issue no longer occurs for me. I used to keep Safari open with tabs for Whatsapp, Tinder, and sometimes long YouTube videos, and now I keep Safari mostly closed.

But I can't say Safari is for sure the issue. Let me run a test for a week to see if it is.

Not saying you're wrong about Apple & older Macs, or even what the cause may be, but one thing that crosses my mind is that older Macs can have a lot of hidden older stuff installed that can cause problems with later updates & upgrades :)

I find this app can point out some of that old failing orv interfering stuff...

http://www.etresoft.com/etrecheck

I had done the etrecheck on mine. When Mojave came out, I went as far as doing a clean install. Literally, reformatting the hard drive and reinstalling from scratch like it was a brand new computer. Once I got everything up and running, the freezes came back when all I had installed was stock Apple software.

That is why I maintain that it is more of a hardware issue than anything, which would also make it a lot more expensive for Apple to fix.

I've been running the past several macOS 10.14.x Public Betas (10.14.5 betas and now 10.14.6b1 build 18G29g) in hopes that I can capture the error and report it. I've experienced it almost daily in all the betas. I've filed multiple Bug Report/Feedback Assistant reports. It creates a System Information Report and sysdiagnose zip file. Several times I kept console.app running and copy/pasted the error message from that (same as everyone gets). There's been no response, follow-up, or any fix for it.

For reference, we have 2 MacBook Pro (Retina, 15-inch, Mid 2015)'s experiencing this. The specs for both are:

2.5 GHz Intel Core i7

16 GB 1600 MHz DDR3

Intel Iris Pro 1536 MB

500GB SSD (APPLE SSD SM0512G)

< 250 Cycle Count on battery

I've done fresh installs, beta installs, stopped using VMWare Fusion and BetterSnapTool (with fresh installs after stopped using both). It might disappear for a couple days after the fresh install then it comes back. Sometimes it happens maybe just once a day. Sometimes it happens several times in an hour. I've had it happen back to back so instead of freezing for 5 seconds it freezes for 10 seconds (verified through console.app that was running).

It's such a horrible experience for a "high end" laptop. I've been experiencing this since at least macOS High Sierra.

Well... I had my mid 2015 MPB 15" screen accidentally cracked. I bought an OEM new replacement for it off ebay (don't have apple support in my country). Replaced it myself and since having the new screen have not seen any more issues... This matches with the people who say using an external screen not seeing the error. The only other thing I did in the process of changing the screen was disconnect the battery from the motherboard.

BorisYeltzen, if you replaced your screen, the other thing you did apart from disconnect the battery is of course disconnect the screen, so this could be a problem with the screen connector not making proper contact, or connector cable oxidising, etc. I think I might open my laptop, disconnect the screen, clean the contacts and reconnect. Perhaps the problem could be due to a component in the screen failing with age, although there are reports here of it happening with very recent and brand new laptops too.

Someone mentioned that this was a video driver issue, and that makes sense, since an application shouldn't be able to freeze the entire system like this. But it does appear to be triggered by something webkit does. I have always avoided Safari, but I have started to see freezes when leaving the app store open as well.

Well, on my iMac it seems that it's related to my TimeMachine (an external RAID set, collecting data from the internal and an external disk).

I had my Activity Monitor running, and found out that every time my Mac froze, one task rose to the top, and it was "backup" process. If I disable the automatic backup in System Prefs, my freeze time is over.

And that is very very welcome thing, while I'm playing World Of Warcraft Classic :-)

I've been having this issue for years, across several upgrades. The only improvement is that finally there's a traceable message that appears in Console with every freeze. In the beginning there was no entry at all. I've tried everything to no avail. Today is the first I've read about a connection to the App Store. I'll have to observe that. I was sure it was a Safari issue, but if they've got App Store running on the same processes I guess there's no difference.

Amazing the downward spiral of Apple quality these days, leaving bug unfixed for so long.

Model Name: MacBook Pro

Model Identifier: MacBookPro11,1

Processor Name: Intel Core i7

Processor Speed: 2.8 GHz

Number of Processors: 1

Total Number of Cores: 2

L2 Cache (per Core): 256 KB

L3 Cache: 4 MB

Hyper-Threading Technology: Enabled

Memory: 16 GB

Boot ROM Version: 156.0.0.0.0

SMC Version (system): 2.16f68

fault	kernel	virtual IOReturn IOAccelEventMachine2::waitForStamp(int32_t, stamp_t, stamp_t *): timeout waiting for IntelAccelerator stamp 3519377 (gpu_stamp=3519376)
fault	kernel	void IOAccelEventMachine2::handleFinishChannelRestart(IOReturn, int32_t, uint32_t) - Setting restart type to 4
fault	kernel	void IOAccelEventMachine2::handleFinishChannelRestart(IOReturn, int32_t, uint32_t): GPURestartDequeued stampIdx=4 type=4 fromWhere=1 waitingOnIdx=4
default	kernel	[IGPU] display event timeout on index = 4
fault	kernel	void IOAccelEventMachine2::restart_channel(): GPURestartSkipped stampIdx=4 type=4
fault	kernel	void IOAccelEventMachine2::restart_channel(): no channel associated with stamp_idx 4 (type 4)

I'm on my 4th day of no freezes. The only thing I've done differently is switch to Vivaldi Browser instead of Safari. Hoping I've found the issue.

Have you reported the issue to bugreport.apple.com? The more we report the more Apple pays attention to the problem.

Bad news... It is back. After not seeing it for over a week since doing a clean install of Mojave, I had two freezes today, and the dreaded:

virtual IOReturn IOAccelEventMachine2::waitForStamp(int32_t, stamp_t, stamp_t *): initial wait for 1 second expired. Continue wait for 4 seconds. stamp 245920 (gpu_stamp=245919)

has returned. I haven't changed anything on my MacBook in the last few days, so I have no idea how I happened to make it a week with the error. I would really love to find out from some one what is happening.

Dear Apple,

Please assist in resolving the ongoing "virtual IOReturn IOAccelEventMachine2/void IOAccelEventMachine2" issue. There are 2-3 years and multiple user reports on this issue and not a single helpful response from corporate. This is not an isolated issue and there are exact and repeated Console output messages for your team to examine. This issue is so frustrating because there is no pattern to its occurrence. There is no sequence of user events/inputs that seem to trigger this issue. There is no specific application running that seems to trigger this issue. There is no timeframe that seems to trigger this issue.

There does appear to be a hardware configuration most at risk:

Here is the Console output for reference:

Model Name: M

There are multiple users with the same issue and you are welcome to contact me directly for further input.

Thank you

macbook pro retina,late 2013

version 10.14

2.6ghz i5

facing the same issue as you mate,

this is the log from my macbook

fault 23:25:55.384138 +0530 kernel virtual IOReturn IOAccelEventMachine2::waitForStamp(int32_t, stamp_t, stamp_t *): initial wait for 1 second expired. Continue wait for 4 seconds. stamp 3071177 (gpu_stamp=3071176)

fault 23:25:59.384447 +0530 kernel virtual IOReturn IOAccelEventMachine2::waitForStamp(int32_t, stamp_t, stamp_t *): timeout waiting for IntelAccelerator stamp 3071177 (gpu_stamp=3071176)

fault 23:25:59.384464 +0530 kernel void IOAccelEventMachine2::handleFinishChannelRestart(IOReturn, int32_t, uint32_t) - Setting restart type to 4

fault 23:25:59.384468 +0530 kernel void IOAccelEventMachine2::handleFinishChannelRestart(IOReturn, int32_t, uint32_t): GPURestartDequeued stampIdx=4 type=4 fromWhere=1 waitingOnIdx=4

fault 23:25:59.384524 +0530 kernel void IOAccelEventMachine2::restart_channel(): GPURestartSkipped stampIdx=4 type=4

fault 23:25:59.384527 +0530 kernel void IOAccelEventMachine2::restart_channel(): no channel associated with stamp_idx 4 (type 4)

fault 02:00:30.128901 +0530 kernel virtual IOReturn IOAccelEventMachine2::waitForStamp(int32_t, stamp_t, stamp_t *): initial wait for 1 second expired. Continue wait for 4 seconds. stamp 3101462 (gpu_stamp=3101461)

fault 02:00:34.130116 +0530 kernel virtual IOReturn IOAccelEventMachine2::waitForStamp(int32_t, stamp_t, stamp_t *): timeout waiting for IntelAccelerator stamp 3101462 (gpu_stamp=3101461)

fault 02:00:34.130132 +0530 kernel void IOAccelEventMachine2::handleFinishChannelRestart(IOReturn, int32_t, uint32_t) - Setting restart type to 4

fault 02:00:34.130136 +0530 kernel void IOAccelEventMachine2::handleFinishChannelRestart(IOReturn, int32_t, uint32_t): GPURestartDequeued stampIdx=4 type=4 fromWhere=1 waitingOnIdx=4

fault 02:00:34.130193 +0530 kernel void IOAccelEventMachine2::restart_channel(): GPURestartSkipped stampIdx=4 type=4

fault 02:00:34.130196 +0530 kernel void IOAccelEventMachine2::restart_channel(): no channel associated with stamp_idx 4 (type 4)

hope apple can look into it, its so annoying, hangs for few seconds many times a day.

Unfortunately the freeze occurs for me under Mail, TextEdit, and other apps to include Safari. I'm really feeling that this issue is being ignored by Apple for whatever reason(s) they may have. If one searches for "virtual IOReturn IOAccelEventMachine2/void IOAccelEventMachine2" Console output messages, you will find multiple reports over multiple years but not one solid answer or resolution to the issue. Clean Installs, V-RAM purges, SMC resets are occasionally suggested, but the freeze issue always returns. I had an Apple Store run their diagnostic and they found no hardware issues. Apple???