For one reason or another, you may need to recapture that extra hard drive space you set aside for Boot Camp. Perhaps you have another machine you’d like to transfer your Windows license over to, and don’t need Boot Camp on your Mac anymore. No matter why you need to get rid of Boot Camp, there is a simple way to get it done without having to format your entire drive and repartition it. You can simply remove Boot Camp. Here’s how to uninstall Boot Camp on OS X:
First, you’re going to want to make sure any files on your Windows installation you need to keep are safely backed up on an external drive or disk. When you remove the Boot Camp partition, you’ll also lose any and all data from that part of the drive. It’s also important to make sure you’ve backed up data on your OS X partition as well, either using Time Machine or copying the important data over to an external drive.
Now, you’re going to need to launch Boot Camp Assistant by either searching in Spotlight (accessible by hitting Command + Spacebar or the magnifying glass in the upper-right corner of the screen), or going to Applications -> Utilities -> Boot Camp Assistant in your Finder.
Once the program is open, you’ll need to hit Continue to get past the Introduction screen of Boot Camp Assistant. You’ll then be presented with two options. You can either choose Create or remove a Windows partition or Start the Windows Installer. For this operation, you’ll need to make sure Create or remove a Windows partition is selected. Then, hit Continue.
Here, there is really only one button to push: Restore. This will remove your Boot Camp partition (and anything in it) and restore your disk to its previous size and setup. Make sure that you don’t power down your system during this process, as it can cause damage to existing partitioning tables and/or data.
Once this is complete, you should see a final window telling you that the Windows partition has been removed and your disk has been restored to a single volume. Congratulations, you’re now free of Boot Camp.