Workaround for Freezing Macs with OS X 10.11.5 and OS X 10.11.4?
As we mentioned months ago, some unlucky Mac users have been experiencing random frequent system freezes since updating to OS X 10.11.4 and/or OS X 10.11.5. The problem is not a subtle one and you’re already well aware if it impacts you; at random, the entire Mac freezes up and becomes unresponsive requiring a forced reboot, something that prior to these releases of El Capitan basically never happened at all.
The freezing issue is difficult to reproduce in any consistently reliable way, but one thing that tends to be commonplace is that Safari is in use when the freezes occur, often viewing web video or a site with embedded web video content in some form. We received a user tip a week ago from a reader who mentioned that disabling WebGL in Safari had basically stopped the incidence of their iMac 5K freezing at random. If your Mac is freezing frequently and randomly requiring a hard reboot since updating to OS X 10.11.5 or OS X 10.11.4 and you want to try this yourself, here’s what you can do:
- From the Safari browser, close any existing windows
- Now pull down the “Safari” menu and choose “Preferences”
- Go to the “Security” tab
- Completely disable WebGL by unchecking the box next to “Allow WebGL” – this may impact performance of some web video and web graphics
- Close Preferences in Safari, then quit and relaunch the app, browse the web as usual
Does this work to prevent the Mac freezing issue? Evidence is purely anecdotal at this point. I’ve had WebGL disabled for a few days now and haven’t had a random freeze-up since with a Retina MacBook Pro 13″ early 2015 model which had been routinely suffering from the freezing issue, (yes it’s still running OS X 10.11.4) and it hasn’t frozen since. This could be purely coincidental, or there could be something to it.
If you’re impacted by the annoying freezing problem, it’s fairly low effort workaround to try disabling WebGL and relaunching Safari yourself, and it just may make a difference.
It’s not clear how widespread the system freezing problem is, but it seems to primarily impact newer model Macs with Retina displays running either OS X EL Capitan 10.11.4 or 10.11.5. There are a multitude of Apple discussion forum threads on the matter here, here, and here, MacRumors gave the problem attention recently, and our user comments also show notable incidence of the issue. It’s a frustrating problem to experience, so hopefully a permanent resolution will arrive from Apple soon.
In the meantime, did turning off WebGL resolve or reduce your Macs random system freezes with OS X 10.11.5 or OS X 10.11.4? Let us know your experience in the comments.