macOS Sierra freeze on iMac late 2009 using Safari

I tried the clean install, but this did not help at all.

I have two almost identical late 2009 21,5" iMacs, one with the ATI Radeon HD4670 card, the other with the basic on-board graphics. The on-board graphics machine does not suffer from freezes, the machine with the ATI Radeon does.

Anyone else with ATI Radeon graphics & freezes?

riadfromhabsheim, maybe editing the thread title (omitting iMac late 2009) would make it clearer that the problem isn't related to a specific mac.

well, 27" iMacs from late 2009 have ATI, mine does as well (and has this Safari freezing problem)

Here's a list of macs with ATI:

Mac computers that use OpenCL and OpenGL graphics - Apple Support

maybe it's ATI/AMD-driver related?

So my late 2009 iMac has been working fine since I did the above (safe boot, First Aid, Recovery...) on 3rd October. Not a single beachball. Just started crashing again today, 10th October.

I also did clean install, have ATI and I get the same freezing with Safari. So I don't think clean install will help. Just installed Chrome...

Same with me (2009 iMac 21.5" with stock ATI graphics card). I did an upgrade though not a clean install; I had done a clean install with Yosemite and this computer (my wife's) is lightly used with same applications as always (Office, Safari, macOS Mail). Hard reboot always required (mouse is alive, but that is about it).

I alos had a stretch of about 10 days with no problems but the problem has reoccured.

When I SSH into the machine, I see that looking at top -u, Windowserver is stuck

I have the exact same problem on my late 2009 iMac after upgrading to Sierra. I have replied and posted to many other similar discussions.

I tried running kextstat | grep -v com.apple in the terminal and saw that I have a "pacesupport" kernel extension running, called com.paceap.kext.pacesupport.snowleopard. I think this is related to iLok, I have a few Logic plugins with this type of license. I'll try and uninstall the iLok license manager to see if this helps.

Same problem here..

27" imac late 2009

I hope to find a way to reboot by using ssh. Simply using a "sudo reboot " won't work.

Erwin

The only way to solve this problem was to completely restore my Mac to El Capitan using Time Machine. Hold command-R right when the computer starts to boot, then select Time Machine Recovery. I didn't have too many issues because I didn't have too many "new" files between Sep 20 and now, I just made a copy of those and transferred them back to my Mac after restoring.

I'm glad I did this, because Finder was crashing EVERY TIME after waking up from sleep.

Since the problem might be related to the ATI graphics, I'm guessing that Safari hardware acceleration might be a problem. I've now switched WebGL to "ask" in Safari settings, to test whether not using hardware acceleration might help to prevent the freezes (with "ask" I can see which sites would have used it - but I will deny for now).

I'll let you know whether this makes any difference.

No luck disabling WebGL, still had the freeze.

Also no luck with a reboot through SSH, although the 'sudo shutdown -r now' did seem to gracefully close all applications and services. No reboot though and still had to keep the power button pressed.