I’m a longtime Mac Pro user with a 5,1 3.2ghz early 2009 quad-core MP. 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. It’s a frustrating problem to experience, so hopefully a permanent resolution will arrive from Apple soon. 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 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. 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. This could be purely coincidental, or there could be something to it. 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. Close Preferences in Safari, then quit and relaunch the app, browse the web as usualĭoes this work to prevent the Mac freezing issue? Evidence is purely anecdotal at this point.Completely disable WebGL by unchecking the box next to “Allow WebGL” – this may impact performance of some web video and web graphics.Now pull down the “Safari” menu and choose “Preferences”.From the Safari browser, close any existing windows.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: 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. 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.

Second monitor imac keeps freezing