Partition Cannot be Deleted

I admit I have made a huge mistake, I tried to remove an item fro the context menu and ended up re installing from CClone. However I now have two partitions on my mac HDD. Split 250 GB and 750GB, I need to delete the 250GB partition but cannot.
I show it in Disk management and "Remove it"but it is still there . My computer is working fine but I have lost 250GB from my hard drive.
I am using CClone and Time machine but last time I tried I ended up with this problem.
Any help gratefully received as I am relatively new to Mac.
Thank you
RP

Have you tried Disk Utility, but make sure your backups are up to date

You can't remove the partition while booted from the drive. You either have to boot with your recovery install disk or boot to your recovery partition in order to remove it. Since you gave us no info about your version of OS X or your machine, that's the only advice we can give you for now.

When posting a question always give us info about your Mac and which version of OS X it's running.

Hi
Thank you for the replies.My system is Mac Mountain Lion 10.8.2 Intel 4gb RAM
I think that I can boot to my CClone external HDD, But can I then just merge the two partitions without loss of my Mountain Lion OS, the 250gb partition which is causing the problem is showing on top of the Mountain Lion partition in Disk Utility.

No, you can't do that via Carbon Copy Cloner. And thanks for posting your version of OS X.

Try this: Boot your machine to its recovery partition: Hold down command + r as soon as you hear the boot chime (bong!). It'll take a bit to boot but eventually you'll be booted into Recovery. From Recovery, select Disk Utility.

Select your hard drive on the left by highlighting it. Now select the "Partition" tab on the right. Select the 250 GB partition by highlighting it. Now press the small minus button at the bottom and then press apply. The 250 GB partition will be removed and you'll have empty space in its place.

Next step is to use your mouse to grab hold of the partition border separator line of your OS X partition and drag it until it fills the entire drive. Press apply.

Exit out of Disk Utility and reboot to normal mode.

Let us know if that works. By the way, since you have a CCC backup if anything goes wrong you can restore.

chscag, thank you for the response. I tried your suggestion this morning but no luck I'm afraid.
I pressed the minus sign and then "Remove" but it is still there. I also have the feeling that the 250 partition is part bootable as I sometimes get asked for login twice.
While I was in Recovery Mode I tested recovery from Time Machine, but when it came to choosing Disks only Mountain Lion was Showing. In Disk Utility it shows At the top "Mac HD Mountain Lion"
Then underneath Mountain Lion, and beneath that Odd Disk (I named the 250 GB partition that for recognition purposes)
I am not sure how I would go about formatting the whole drive, and if I restore from either CClone or Time Machine I could finish up in exactly the same position.
Thank you for your help, I appreciate it.
RP

While booted up into the OS and opening Disk Utility - If per your previous post - the 250GB partition is the shown as the top / 1st partition on the drive and OS X is installed on the 2nd partition, I think you're going to have to blow everything away, create a single partition and reinstall to get that space back.

Can you verify that is the case?

You could do that by booting to your CCC backup, opening Disk Utility, select the internal drive and use the Partition tab to have it create a single partition. Then open up CCC and clone it to your internal drive.

Not using CCC here, but have been told it does create the ML recovery partition - perhaps wait for more input from chscag on that.

Hii bobtomay, That is absolutely correct, and I think you are right in what you suggest. I will wait and see what any other input says before I try.
Thank you for your response.
RP

My only concern is making sure you have the recovery partition on the internal drive once you're finished and I have not done a restore from a backup since this whole new thing with Lion and ML started.

Just a quick question, if I don't clear the extra partition is it any detriment to leave it alone apart from losing 250GB from my hard drive.
After making the error I did, I am just a bit wary of formatting and restoring from CClone.
Also which is best to restore Time Machine or CClone?
Thanks
RP

I am still using SuperDuper! here instead of CCC, along with Time Machine.
SuperDuper however does not clone the recovery partition, so at some point I need to switch to CCC also.

I have done all of my restores from my bootable backups.
Much faster because you bypass the need to reinstall the OS first which is required for a Time Machine restore.

Plus, from all I've read, some apps will still need to be reinstalled after a Time Machine restore (MS Office, et al) which is not the case when restoring from a bootable backup.

OK, I decide to try the suggestion. I booted into CClone OS and the tried again to delete the offending partition with the same result no change, so I clicked on Repair Disk having Highlighted Mac HD Mountain Lion. The info at the bottom it only showed 750GB while it was running. It's as if the 250 GB partition is not recognised at all by the computer.
Any other suggestions?
Thank you
RP

Did you use the Partition tab in Disk Utility?
You shouldn't be trying to delete any partitions.

Select the drive - change the Partition Layout drop down from Current to 1 Partition - enter a name for your partition

OK, I have managed it. Let me explain, I couldn't do as you suggested as all the options in partition wee greyed out except the minus sign which didn't work.
There seemed to be nothing on the partition and as it was at the top of the Disk utility list I couldn't do anything with it.
This is what I did, I restored Mountain Lion to it from the 750 partition, then erased the 750 partition and then I was able to extend the 250 GB partition to the full 1TB size.
Everything is now working perfectly.
I thank you all for your input and assistance, this is surely an excellent forum for Mac learners such as myself.
RP

That was sure one way to do it. Glad you got it sorted.

My guess - you had the 250GB partition selected in the left pane instead of the hard drive itself. For next time you run into this - take a look at my pics above and you'll see I have the drive selected, not one of the partitions in the drive.

Just to make it clear, I did the restore using the "Restore" facility in Disk Utility. It only took 17 minutes.
No I had selected the main 1 TB hard drive
Thanks to all
RP