how to format the wrong formatted os ssd
Hi,
I have a macbook air 13 2011 with 128 Gb capacity. I think I made a mistake by restoring the os SSD with the time machine backup which is stored in an external disk. What I did is restart-->command+R-->disk utility-->click to choose the machitosh HD and choose restore--> using external disk containing time machine backup as source and machitosh HD as destination. After copying, I took off the external disk and restart. Now I realized it is in trouble because it can't to be booted and go to OS X utility directly.
My trial to solve this problem:
1. reinstall the OS X: failed, it said the SSD is locked.
2. go to disk utility and try to erase/partition the SSD: failed, it said "couldn't unmount the disk".
3. clike the SSD and choose unmount : failed, could not be unmounted.
4. go to the terminal and unmount the disk. I tried commande "diskutil unmount (and unmountDisk) /dev/diskls1 or 2 (I forgot the exact number), failed. It is said that "at least one of the volume can't be unmount.
I don't know what to do right now. Is there a way I can force to format the SSD and reinstall the OS? Thanks
Dan
MacBook Air, OS X Yosemite (10.10.3)