Unable to create BootCamp partition with Snow Leopard

Recently I was trying to install Windows on my Mac to run SolidWorks (yes, it's Windows Only). However, for some reason, Snow Leopard's bootcamp assistant refused to create a partition for me. It kept saying:

The disk cannot be partitioned because some files cannot be moved.

Back up the disk and use Disk Utility to format it as a single Mac OS Extended (Journaled) volume. Restore your information to the disk and try using Boot Camp Assistant again.

I had created a Bootcamp partition once before with Leopard so I was puzzled when something Mac wasn't working! (Okay, no, Apple's computers are just as fallible as other computers). And there was no was I was going to go through formating the hard drive again, installing Windows would take long enough!

However, after trying several different things I was finally able to get Snow Leopard to partition the hard drive so that I could get Windows 7 to work. I'm not sure what worked, but I'm pretty sure that others are likely to have similar problems, which is why I took the time to write this post.

Step 1: Verify and Repair thy hard drive

First I put in my Snow Leopard DVD (this should also work for Tiger and Leopard) and pressed C on my Mac after restarting the computer to boot from my Snow Leopard DVD. After choosing English as my language:

• I clicked Utitilities in the menubar
  
• Clicked Disk Utility
• Selected my hard drive (Macintosh HD) in the drives list on the left hand side
• Clicked on the First Aid tab and clicked Verify Disk
• After it verified my disk I clicked Repair Disk

Disk utility then took the time to do some stuff and told me that it repaired some corrupt volume headers. And it also told me that the file count was wrong, and it repaired that as well. Then I restarted my comptuer normally into OS X, and tried BootCamp assistant again. Your quest to seek a Windows partition might here, if a mere repair disk was necessary. If not continue reading...

Step 2: Behold the power of fsck!

So after restarting into OS X, BootCamp assistant still didn't want to partition my hard drive so I tried fsck (a command-line utility to repair disks) to repair my disk drive which ultimately did the job!

If you want to read more about fsck and how to use it, you can try Apple's help page or just follow my (foot)steps. Here's what I did:

1. Restart the computer, and while it's restarting (before you get the Apple logo boot screen!) hold down "Command (or the Apple Key) and S" together to start up your computer in "single user mode"
2. Don't worry about the black text, you're computer is still ok
3. When OS X gives you a cursor and asks you what to do next, type in:
   

   /sbin/fsck -fy

4. Press enter
   
5. OS X will do its thing and tell you after it's done
6. Type in
   

   reboot

7. Press enter
   
8. Your computer will restart into OS X the normal way

Now try BootCamp again. This time BootCamp assistant should work, or at least it did for me! After looking around on a couple of forums, it seems that using a professional "disk defrag" tool for a Mac (yeah, defrag a mac!) seemed to have worked for a few people. But I personally like the free options ;).

Happy camping!