Cannot delete Yosemite partition

[Tex-Twil]

Hi,
I installed Yosemite on a 2nd partition and now I want to get rid of it. When I boot to Mavericks, Disk Utility does not allow me to modify any of the two partitions ( - button disabled). When I boot to Recovery 10.9, I can only delete my Mavericks partition but not the Yosemite one. The - button is disabled when I select the 2nd partition.

How can I remove it ?

cheers

 

[maflynn]

Did you try to boot up in the recovery partition to try to delete it.

 

[Tex-Twil]

Did you try to boot up in the recovery partition to try to delete it.

Yes, see my post.

 

[Bruno09]

Do you have : "Type : Logical Volume Group" in the bottom of the Disk Utility window ?

If yes, this post should help : https://forums.macrumors.com/showthread.php?p=19494134#post19494134

 

[Tex-Twil]

Do you have : "Type : Logical Volume Group" in the bottom of the Disk Utility window ?

If yes, this post should help : https://forums.macrumors.com/showthread.php?p=19494134#post19494134

diskutil cs revert disk1

thanks!