I followed the instructions on <a href="https://apple.stackexchange.com/questions/139157/restore-macintosh-hd-to-its-original-partition-configuration">this link</a> (last answer) to delete the Core Storage Logical Volume Group via terminal while pressing Cmd+R during startup. These are the functions I used in terminal: diskutil cs list diskutil cs delete <Logical Volume Group UUID> Now I cannot resize the partition via Disk Utility. The post mentioned that a red error message would appear when selecting the drive, but that didn't happen. I'm stuck! When I try entering "diskutil cs list" in Terminal it returns: No CoreStorage" logical volume groups found." These are screenshots from the errors in Disk Utility: ![enter image description here][1] After resizing the top partition by dragging down and clicking "Apply", an error message prompts: "Couldn't unmount disk". Also happens after I repair the disk. ![enter image description here][2] When restarting the computer, a grey screen with error icon appears. ![enter image description here][3] Any help would be greatly appreciated! [1]: https://i.sstatic.net/v3TgK.jpg [2]: https://i.sstatic.net/d1HwR.jpg [3]: https://i.sstatic.net/uF4y7.jpg