How to resize your Boot Camp partition without reinstalling Windows

February 18th, 2009 • 10 comments
Tags: Boot Camp, Carbon Copy Cloner, mac, repartition, WinClone, Windows

If you’re a hardcore gamer, using Boot Camp to run Windows on your Mac is a fact of life. If you enjoy the MacOS, you’ll probably find yourself devoting as little of your hard disk as possible to your Windows partition. As you accumulate more games, you’re bound to hit capacity on your Windows partition. Your next step is to restore your disk to a single partition, recreate your Windows partition, and reinstall both Windows and all your games. That is certainly no fun… especially if your games have to be redownloaded from Steam or a similar service.

This method will allow you to resize your partition, and, with just a little extra work, restore everything back to it’s former state after having created your new and larger Windows partition. You’ll need some software and (possibly) some hardware to get started. Download and install both WinClone and Carbon Copy Cloner. Both of these applications are free. Have a Windows XP CD at hand (just in case). You may also need an external hard drive for one of two reasons: First, you will need enough free space to store an image of your entire Windows partition. If you have that much space on your drive already, you won’t need the external drive for that purpose. Second, you may need to repartition your entire hard drive and restore even your Mac partition from an external drive in case the MacOS is unable to recreate your Windows partition after merging the old partition back into your Mac partition (This happened to me just the last time I resized so it is not infrequent.). If you end up needing a drive for this reason and don’t have one, you may have to do without a Windows partition until you can procure a drive. If you’re OK with this, feel free to start the process without an external hard drive (assuming you have adequate free space to image the Windows partition). If you run into both issues, you may need two drives to get you through. If you’re looking to buy a drive, I like the Western Digital Passports as a nice portable external drive (500GB, 320GB, 250GB, 160GB).

Once you have the software installed and the necessary hardware at hand, you’re ready to begin.

Fire up WinClone and point it toward your existing Windows partition. You can tell you have the correct partition by the “Total size” field in the program.

Image the partition to a location on your Mac partition (if you have the space) or on your external drive. This will take a little while.

Once you have the image, go into your Boot Camp Assistant in /Applications/Utilities/’

Click “Continue” from the first screen. Next, select “Create or remove a Windows partition” and click “Continue” again. Now, it will tell you that your drive will be restored to a single Mac-formatted partition. Don’t get scared because we have an image of everything in the Windows partition that will be deleted. You won’t lose data (or savegames .

Once the restore is complete, relaunch the Boot Camp Assistant. This time you want to create a Windows partiton. Size it however you like. Start the creation process. This is where the steps will fork a bit. If it is able to create the partition, you’re in luck because you’re almost done. Just relaunch WinClone, click the “Restore” tab, click “Select image,” and find the Windows image you created earlier. Once the restore is complete, boot into Windows. It will run ScanDisk. This is normal so don’t panic. Once this is complete, you should be booted into Windows with everything you had previously… except with the addition of an extra chunk of hard disk capacity!

If Boot Camp Assistant fails to recreate the Windows partition, you’re in for a few more hours of work. First, connect your external drive. If you had to put the image of your Windows partition on an external drive, you will need a separate one for this backup.

We need to make sure it is formatted properly to be bootable on your Mac. Run Disk Utility from /Applications/Utilities/. Select your external drive (the drive not the partition) from the left-hand pane. Select the “Partition” tab on the right. Under “Volume Scheme:” select “1 Partition.” Click the “Options” button at the bottom.

If your drive is a PC-formatted drive, the “Master Boot Record” option will probably be selected. Select “GUID Partition Table” instead. This is the magic setting that makes a drive bootable on an Intel Mac. This is very important later on as this drive will not only be your backup of your entire Mac drive but the OS you will boot to in order to format and restore to your internal drive. Click the “OK” button.

Now click the “Apply” button to start the format process. Once this is complete, start up Carbon Copy Cloner.

Select your Mac partition as the source disk. The destination will be your external hard drive. Click the “Clone” button to start the process. Depending on how much data you have, this may take a while. You should probably fire up the Xbox 360 or maybe a movie or something. Maybe you could go out to eat!

Now that we have your entire drive backed up, we need to boot to the backup so we can reformat the original drive. Leave your external drive connected. Restart your Mac and hold down the “Option” key after you hear the chime. You should see your external drive among the other connected bootable drives. Click on the external drive.

The OS should boot and look just like it would if you had booted from the internal drive. Fire up Disk Utility again (/Applications/Utilities/). This time, select your internal drive from the left-hand pane. Click the “Erase” tab. Make sure the format is “Mac OS Extended (Journaled)” and click the “Erase…” button. Click “Erase” in the dialog box to confim. This shouldn’t take long. Once the drive is erased, start Carbon Copy Cloner again.

This time around, the source disk is your external drive; the target is your internal drive. Click clone. This will take about as long as the initial clone.

Once the clone is completed, restart the Mac. Hold “Option” after the chime and boot to the internal drive. Now, boot to your internal drive. Start the Boot Camp Assistant (/Applications/Utilities/) and create a Windows partition. If you want your XP partition formatted NTFS, you’ll need to insert your XP disc and allow the computer to start the installer. You need only let the Windows installer format your partition. There’s no need to proceed with the install. If you just want to use the FAT32 file system created by default by Boot Camp, you can skip this step.

Boot back into MacOS. The rest of the steps are the same as the steps following a successful re-creation of the Windows partition. I will copy and paste them below for your convenience. Relaunch WinClone, click the “Restore” tab, click “Select image,” and find the Windows image you created earlier. Once the restore is complete, boot into Windows. It will run ScanDisk. This is normal so don’t panic. Once this is complete, you should be booted into Windows with everything you had previously… except with the addition of an extra chunk of hard disk capacity!

If you had to take this fork, it was a long road, but you’re here at the end. Congratulations! Now, get to installing some more games (or productivity apps if you must).

I realize there are programs to do this automatically for you, but those cost money. If you’ve just laid down $50 on that hot new game, you probably don’t have much more cash to buy a program to do something you may only ever do once or twice. This method, although convoluted, will get you there mostly for free. Do you have an easier method (or can you refine mine to make it better)? Let’s hear about it in the comments.