Cannot unmount disk to format it

[faqyoutom]

I failed to install Lion on my pc. Now I am trying to install win8 on it but it wont let me cos of the GPT so I tried to erase my disk to Ms-dos FATso i can install win on it but it stucks at Unmounting disk. I am booting from my DVD

[bigben1]

if you can get into command prompt , run as an administrator, run following commands

diskpart     enter

list disk     enter

you should have lists of hdds on pc as

 

disk0

disk1 ..............check one with gpt partition(for example  disk1)

;etc

 select disk1    enter,    once gpt disk selected

clean enter               and thats all.

if you have another windows pc , you can connect hdd to it and do as above.

hth

[faqyoutom]

After it says unable to write to the last block

Unfortunately all I have is my iPad nothung else right now

[joe_black]

Run your Lion DVD, open Terminal and enter this.

 

sudo diskutil umount -f /Volumes/YourPartitionName

 

Close Terminal, open Disk Utility. (Still in Lion Installer)

Format it FAT, then run Windows DVD and format to NTFS/FAT.

 

Make sure the drive is MBR for Windows DVD as well.

 

* If that Terminal command doesn't work then try: 

sudo diskutil umount force /Volumes/YourPartitionName

[faqyoutom]

It says -bash: sudo: command not found

bigben1 you are the biggest mother fkin BOSS!!! Thanks it {censored}in worked