OS X 10.10 Yosemite

Symptom: After installation of the ownCloud client, the Finder overlay icons indicating synchronization state of a particular file/folder didn’t work. The Extensions control panel of System Preferences didn’t include the corresponding symbol.

A look at /var/log/system/log revealed repeated error messages like

May 19 09:07:23 theoryc9 kernel[0]: Sandbox: coresymbolicatio(1250) System Policy: deny(1) file-write-create /System/Library/Caches/com.apple.coresymbolicationd
May 19 09:07:23 theoryc9 coresymbolicationd[1250]: /System/Library/Caches/com.apple.coresymbolicationd/data does not exist, resetting cache
May 19 09:07:23 theoryc9 coresymbolicationd[1250]: Attempt to create [/System/Library/Caches/com.apple.coresymbolicationd/data] failed. No such file or directory
May 19 09:07:23 theoryc9 coresymbolicationd[1250]: Unable to open storage at /System/Library/Caches/com.apple.coresymbolicationd/data
May 19 09:07:23 theoryc9 com.apple.xpc.launchd[1] (com.apple.coresymbolicationd): Service only ran for 0 seconds. Pushing respawn out by 10 seconds.

Indeed creating a file or folder in /System/Library/Caches was impossible due to the SIP (System Integrity Protection) feature of OS X introduced in El Capitan, prohibiting write access to certain paths including /System. So we have to do the following to reenable writing to /System/Library/Caches:

  • Start up in Recovery mode. Select a language, if prompted. The OS X Utilities screen will appear.

  • If you use FileVault 2, launch Disk Utility, then select the icon of the FileVault volume (“Macintosh HD” unless you gave it a different name.) Choose Unlock… from the File menu and enter your login password when prompted. Then quit Disk Utility to be returned to the main screen.

  • From the Utilities menu, select Terminal

  • Type (replace “Macintosh HD” with the name of the volume you have the cache problem with)

chflags -R norestricted "/Volumes/Macintosh HD/System/Library/Caches"

  • Quit Terminal to be returned to the main screen and select Restart from the  menu.

  • Log in as an admin user, open Terminal and type (all on one line)

sudo /usr/libexec/xpchelper --rebuild-cache && sudo /usr/libexec/AppSandbox/app_sandbox_cache_builder --rebuild-cache