Help deleting Boot Camp partition

[newcoyote]

Some time ago I had Windows running on my Mac. I don't remember how I did it but I removed Windows(obvious to me now, incorrectly) but not the partition. I know you're supposed to properly remove it in the Boot Camp Assistant .The option to "Install or Remove or Windows 7 or later version" in the first part of BCA is dimmed and not an option.I can see it but cannot select it. I can still find the Boot Camp disk image and that is has the original space (100MB) I allocated when I first set it up. I want to install Windows again but need to start from a clean slate. How can I completely delete this partition and restore to a single partition OS X volume. Thanks for any help.
Yosemite 10.10.2 on a iMac late 2012.

 

[Bomb Bloke]

Did Boot Camp Assistant really let you allocate just 100mb to Windows? That doesn't sound right...

I suspect that if you hold Option when booting the Mac, the resulting startup manager screen should allow you to boot off your Windows installer, which if you're very lucky will in turn let you use the already-existing partition you dedicated to Windows... bearing in mind that a 100mb partition is in no way suitable, but 100gb should be just fine.

Though I've got a memory that this doesn't work, for some reason, and you really need to convince the Assistant to reboot the computer from your installer for things to "click". Hmm. Worth a shot, anyway.

Failing that, the only way I'm aware of to fix a case where a Bootcamp partition was removed without using the Bootcamp Assistant is to wipe the whole drive (removing OS X and anything else on there), and start over from scratch with a new partitioning table. It's possible that there's some third-party tool out there that can fix the mess without resorting to that sort of solution, but I'm not aware of one.

If you do get the Windows installer to boot, but aren't sure where to tell it to install Windows, best not to guess - report back and ask. You may end up taking out your OS X install by accident.

Of course, if you have a full Time Machine backup you should be able to pull yourself out of most messes. If you don't, it'd be a great idea to make one before you go any further with this.

 

[newcoyote]

Did Boot Camp Assistant really let you allocate just 100mb to Windows? That doesn't sound right...

I suspect that if you hold Option when booting the Mac, the resulting startup manager screen should allow you to boot off your Windows installer, which if you're very lucky will in turn let you use the already-existing partition you dedicated to Windows... bearing in mind that a 100mb partition is in no way suitable, but 100gb should be just fine.

Though I've got a memory that this doesn't work, for some reason, and you really need to convince the Assistant to reboot the computer from your installer for things to "click". Hmm. Worth a shot, anyway.

Failing that, the only way I'm aware of to fix a case where a Bootcamp partition was removed without using the Bootcamp Assistant is to wipe the whole drive (removing OS X and anything else on there), and start over from scratch with a new partitioning table. It's possible that there's some third-party tool out there that can fix the mess without resorting to that sort of solution, but I'm not aware of one.

If you do get the Windows installer to boot, but aren't sure where to tell it to install Windows, best not to guess - report back and ask. You may end up taking out your OS X install by accident.

Of course, if you have a full Time Machine backup you should be able to pull yourself out of most messes. If you don't, it'd be a great idea to make one before you go any further with this.

Hi. Thanks for the input. No that was just a typo. You're correct of course. 100GB not MB.
For future reference http://www.mac-forums.com/forums/running-windows-anything-else-your-mac/323170-complete-redo.html this seems to have done the trick.

 

[Bomb Bloke]

Ah. You went with the whole drive wipe? Sorry you didn't find an easier way.