Disk Utility trouble after deleting Windows partition

On my mac book pro, I had loaded windows on a partition (34GB) of the HD. I had used Tuxera.
I have now deleted that partition. However, I am unable to create a Mac OS extended partition from the unused space.

When I try to create a MAC OS extended partition out of the free space, it does not do anything. When I try to repair the HD, it says the "MAC" partition can't be unmounted.

How do I go about either adding the 34Gb to my main MAC OS partiton or create an extended partition for general storage ?


You should be able to do that from within Disk Utility.
Click on the manufacturer's info line - not a partition name - and click the Partition tab.
Click and drag the bottom edge of the Mac OS partition, so it extends across the unused space.
Click the "Apply" button.
If that doesn't seem to work, experiment with the divider lines to see what DOES work. You can play around with those partition sizes safely, as you can always cancel without saving the changes, and nothing REALLY happens until you click that Apply button.
If the partitions can't be modified at all - then likely your only choice to retrieve the space is to back up your Mac OS partition, then delete all partitions by choosing the Partition Layout dropdown, then 1 partition, and click the Apply button, which ERASES everything on your drive, and leaves you with a single partition. Restore your Mac OS partition to your hard drive, and you're back in business!
(if you have an older Mac OS system, then Partition Layout may be called "Volume Scheme", but the process is the same...)