Turning off Wi-Fi in Mavericks is causing some older (and not-so-old) Mac’s to freeze almost instantly and then again during boot, repeatedly. I’m not sure why 10.9 (build 13A603) is freezing when wi-fi is disabled, but another (really bad) defect is freezing Mavericks at boot during the initialization of the wi-fi ethernet adapter (usually interface en1) when it is disabled.
You cannot fix this problem with Safe Boot, Repair Permissions, Repair Disk, re-install Mavericks, restore from Time Machine backup, reset the SMC, reset PRAM, or boot into single-user mode. Thus far, the only solution is to boot from a (homemade) Install OS X Mavericks USB, erase the hard drive, perform a clean Mavericks install, re-install your applications, and manually restore your data. And if you innocently turn off wi-fi again, you will have to repeat this procedure. However, I have worked out an alternative solution…
The work-around is to manually enable the wi-fi Ethernet adapter in the system configuration. Specifically, the PowerEnabled setting in /Library/Preferences/SystemConfiguration/preferences.plist needs to be changed from ‘false’ to ‘true’:
This change, however, is not straightforward. In short, you need to boot from the Install OS X Mavericks USB, and edit this file in the primary volume (e.g. /Volumes/MacBook Pro HD.) You cannot perform this edit in single-user mode because it boots from primary volume, which is read-only in this case. (Perhaps the primary volume is read-write if you boot from the Recovery HD volume, but I have not tried that yet.) Once you’ve booted, open the Terminal application from the Utilities pull-down menu and change directory to /Volumes/<primary volume>/Library/Preferences/SystemConfiguration. Make a backup copy of preferences.plist, and use vi or emacs (under /Volumes/<primary volume>/usr/bin) to make the required edit. Repair Permissions afterwards to be safe and reboot normally.
I was ready to buy a new MacBook Pro during the upcoming Black Friday sales, but I am happy to leave wi-fi on until Apple fixes this #$@&*! issue and save $2500.
Questions, comments and criticism are welcomed.