My iMac appears to be one of the models which has been suffering from sporadic freezing since I installed OS X 10.11.4. Since then, I have been trying different suggested remedies, and think that I may have come across one way of reducing the frequency of freezing. If your Mac is affected, I suggest you might like to give it a go.
A week ago, for no particular reason, my Mac froze and restarted twice within twenty-four hours. It had not done that before – usually these problems occurred every three or four days. What was also unusual this time was that both freezes occurred when there were no apps open other than the Finder, and the display was sleeping, in the small hours when I too was asleep. On both occasions, when it automatically restarted, the log filled with a ridiculous number of warnings and errors, at a rate of over 4000 an hour.
This drove me to perform some radical surgery on /System/Library and /Library, to try to prevent such frequent and loquacious problems. Things seem to be better now, and sometimes it can even take more than twelve hours to accumulate 4000 log entries. Here is what I did.
I created a folder in my ~/Documents folder named OldCruft. This holds copies of extensions and other items which I have removed from Library folders. Within that, I have a folder named libext, for example, which holds KEXT files which I have removed from /Library/Extensions. It is worth doing this in case you need to reverse any of these steps. The alternative will be to install the 10.11.5 Combo updater, or even OS X itself.
First I removed known old and wobbly items, such as the various files supporting my X-Rite ColorMunki Design hardware. These are already known to cause startup crashes on occasion, and I am afraid must go first in order to stabilise OS X.
I then removed each of the following files, by first copying them to their respective folder in OldCruft, then trashing the original:
- from /Library/Extensions: ACS6x.kext, ArcMSR.kext, ATTOCelerityFC8.kext, ATTOExpressSASHBA2.kext, ATTOExpressSASRAID2.kext, CalDigitHDProDrv.kext, HighPointIOP.kext, HighPointRR.kext, Pen Tablet.kext, SoftRAID.kext, SoundflowerSigned.kext;
- from /Library/Internet Plug-ins: AdobeExManDetect.plugin, GarminGpsControl.plugin, Google Earth plugins (all), Mathematica.plugin, OfficeLiveBrowser.plugin, Unity Web Player.plugin, all Wacom plugins, webclient.plugin;
- from /Library/LaunchAgents: com.google plists, com.xrite plists, and org.macosforge.xquartx plists;
- from /Library/LaunchDaemons: com.google plists, com.gopro plists, com.livescribe plists, com.leapmotion plists, com.tclementdev plists, com.xrite plists, and several more;
- all non-standard preference panes from /Library/PreferencePanes;
- from /System/Library/Extensions: all EyeTV kexts, hp_fax_io.kext, JMicronATA.kext, LivescribeSmartpen.kext, TabletDriverCFPlugin.bundle.
These are support files for third-party products, and most were probably migrated from my previous iMac. Many had creation dates earlier than 2014, a few were much older than that. Once they had been removed, I restarted my iMac.
Those who recall the dire warnings over what Apple’s SIP does and does not do may be surprised that you can remove third-party extensions and other files from /System/Library/Extensions and similar protected folders. The constraints imposed by SIP apply to Apple’s files: third-party extensions can still be removed, although you need to authenticate as an admin user first.
I should also point out that, although El Capitan screens kernel extensions and will disable many, all the above KEXTs are approved according to the current settings for that protection.
If you have been plagued by this problem with freezes, please try the above, and let us know whether it reduces the frequency of your problems.