To perform a clean install on your MAC, simply insert the USB drive that you created, power on the computer, and hold down the key to access the boot selection menu. Now Hide the system files again using this command on terminal windowĭefaults write AppleShowAllFiles NO Now copy the Packages folder from Step 10 and paste it into the Installation folder that you just opened in previous step. Here, open the “System” > “Installation” folders and move the Packages file to trash. Once the restore process is done, you will see a new window son your screen. From here click on Erase to start the restore process, then enter in your admin password and hit OK to proceed. Also, drag the BaseSystem.dmg to the Source path Now drag the partition from the device list to the Destination box. Switch back to Disk Utility.app to select the partition name created in step 3. Now you will see three more files next to the Package folder (Step 10) Enter the below mention two commands one by one:-ĭefaults write AppleShowAllFiles TRUE Launch Terminal.app to enter a command to unhide the file and folder on your MAC. First, we need to unhide the files located in this newly mounted OS X Install ESD image. Don’t do anything with this Packages folder just yet. Once the verify process is done you will see the Package Folder. This will start the verify process on your MAC. Now navigate to Contents -> SharedSupport and open InstallESD.dmg Right-click the installer and select Show Package Contents from the context menu. Go to Applications again and find the Install OS X 10.10 Developer Preview app that you downloaded. Now the USB part is over and lets move to the OS X Yosemite installer package.

How to make os x boot disk