Make sure you backup first.

The Combo Update is not working for a bunch of us. The Combo Update only works to update 10.10.0 to 10.10.2 which is different from past Combo Updaters. Either wait until Apple fixes it or use the Software Update from the App Store app to upgrade to 10.10.2.

Repair Permissions using the Disk Utility on the drive to be updated;*

Backup your current installation using Carbon Copy Cloner or SuperDuper;

Download the latest MultiBeast for Yosemite;

Download the Software Update or the

Re-boot;

Run MultiBeast for Yosemite and just select your audio driver to install and, optionally, the 10.10.x TRIM patch;

Re-boot; and

Repair Permissions again.*​ Repair Permissions using the Disk Utility on the drive to be updated;*Backup your current installation using Carbon Copy Cloner or SuperDuper;Download the latest MultiBeast for Yosemite;Download the Software Update or the Combo Update and run it to update to 10.10.2;Re-boot;Run MultiBeast for Yosemite and just select your audio driver to install and, optionally, the 10.10.x TRIM patch;Re-boot; andRepair Permissions again.*​

Code: sudo diskutil repairPermissions /

- This may break some of your Yosemite functions, like audio and TRIM. So, being an Early Adopter is fraught with problems.- If you're using nVidia drivers for your GeForce GTX 750, 750Ti, 960, 970, and/or 980 'Maxwell' graphics cards, you'll need to install the 10.10.2 driver(s) after the 10.10.2 update. See my Post here for the installation upgrade procedures for 10.10.2.Here's the step by step way to update:If you have TRIM enabled, check to see if it was affected by this update.: If you encounter no audio after wake-up from sleep, here are several methods to "fix" the issue; see http://www.tonymacx86.com/audio/151504-no-audio-after-sleep-wake-realtek-alc-applehda-fixes.html . For posting audio problems, see http://www.tonymacx86.com/audio/143752-no-audio-devices-realtek-alc-applehda-guide.html#post886726 * You can use the Terminal instead of Disk Utility if you feel comfortable with a UNIX command: