I decided to update this handy script to fix some bugs and ensure compatibility with El Capitan. You can find it on my Downloads page or here.
Here are some instructions from the old tool. Ignore the old text in the pics.
If you get the error “Mount of outer dmg failed.” you will need to start over. I was able to get it to work by formatting the flash drive by hand and then re-running the program.
Requirements: SUPER IMPORTANT
Install OS X Mavericks , Yosemite, or El Capitan – From the App Store – It is free so go get it.
One 8 GB USB Flash Drive – you could use an external hard drive but why when an 8GB thumb drive is 6 bucks.
Name your flash drive something that does NOT have ANY SPACES!!! i.e. flashdrive is acceptable but flash drive will break.
Once you have both of those run my apple script. The script will ask you to choose your install media, that would be the 8GB flash drive, as well as the location of your Install OS X Mavericks installer. Below is what the process looks like.
1. Launch the Applescript. Click OK after you read the dialog box.
3. This screen should validate that you selected the correct drive to create your Mavericks boot disk. Once you click OK it will format the drive as a GUID bootable disk. This is absolutely necessary in order to create the proper partitioning scheme that OS X can boot from. If you use an external drive or a thumb drive that has multiple partitions it will destroy all of those extra partitions, hence my suggestion of a dedicated thumb drive.
7. Once you have entered the correct password you should see the process start and something that looks like the following. The time it takes will very. On really fast disks it only takes 3 to 5 minutes. On the thumb drive I used it took closer to 20 to 25 mins. BE PATIENT!
8. If everything worked correctly you should see this.