Disk Erase Failed. Disk cannot be dismounted on Mac Mini Server

Question

Level 1

4 points

Disk Erase Failed. Disk cannot be dismounted on Mac Mini Server

Ok, this is a bit crazy for me anyway. I have a Mac Mini Server running Snow. My Server HD failed but fortunately my Mac HD was being used as an image backup and I can boot from it fine and runs perfect. The bad disk was not showing in Disk Utility at all. So I bought a new one and replaced it.

Now Disk Utility sees it but if I try to format it or partition it, I get the message the it cannot be dismounted. I tried re-setting NVRam (Optio+CMD+P+R) but n luck.

I have my original Snow DVD but I have no external DVD. I have a MacBook Pro Mountain Lion.

How do I erase my new disk so I can copy everything back?

Any help is appreciate it.

Posted on Sep 29, 2012 3:11 PM

Reply

Answer 1

Best reply

Alberto Ravasio

Level 5

4,279 points

Oct 1, 2012 1:38 AM in response to wyattbiker

You can start the Mac mini server in target mode, attach the mini to the other Mac and initialize the mini disk using Disk Utility on the main Mac.

Reply

Answer 2

wyattbiker Author

Level 1

4 points

Oct 1, 2012 6:56 AM in response to Alberto Ravasio

Although thats an excellent suggestion but in the end I attached an old usb backup drive and restarted and held down the Option key to select it to boot. Then it went into Disk Utility, and I reimaged the 2nd drive to the new drive. After the reimage I restarted and held down the Option key to allow me to select the first drive.

The only issue I had was to rename my boot drive back to Server HD, which I did by using Finder and one more restart.

I guess the rule is you cannot unmount the boot original boot drive unless you boot from an external drive.

All is good now and thank you.

Reply