OS X Base System Locked

[iosmike]

Background of my question:

1. I have a macmini 2012. I ran Command + R and clicked Disk Utility. I picked "Macintosh HD" , clicked "First Aid", nothing showed to fix. Then I clicked "Unmount" by mistake;

2. Now only OS X Base System shows in Disk Utility (as attached photo);

3. Now I want to reinstall operating system and only available disk is OS X Base System, but it is locked.

4. Is it possible to use the Unmounted Macintosh HD ?

Can anyone help? What steps should I follow?

Thanks,

Mike

 

[Weaselboy]

Was there something else going on before this that made you even try this?

I ask because just unmounting the volume would not cause this. You should still be able to see the volume and be able to rich click it in DU and mount.

 

[iosmike]

Was there something else going on before this that made you even try this?

I ask because just unmounting the volume would not cause this. You should still be able to see the volume and be able to rich click it in DU and mount.

Thanks for asking. Last weekend I upgraded my system and on Tuesday evening the macmini could not start. The bar under the Apple logo was full but stayed there forever. Then I reinstalled the system, but same thing happed. I rebooted and entered into Disk Utility, what happened next is like I described above.

 

[Weaselboy]

Thanks for asking. Last weekend I upgraded my system and on Tuesday evening the macmini could not start. The bar under the Apple logo was full but stayed there forever. Then I reinstalled the system, but same thing happed. I rebooted and entered into Disk Utility, what happened next is like I described above.

Hmmm.... not good. Short of a drive failure, the OS should not just disappear like that. If you want to give it a shot, you can try to reinstall following my instructions in this post and see if it works. But I'm skeptical.

I'm thinking you have a bad drive there.

 

[iosmike]

Hmmm.... not good. Short of a drive failure, the OS should not just disappear like that. If you want to give it a shot, you can try to reinstall following my instructions in this post and see if it works. But I'm skeptical.

I'm thinking you have a bad drive there.

Ok, I will try tonight when I am home. By the way, I ran "First Aid" for Macintosh HD before clickig "Unmount". Nothing showed to fix.

 

[hobowankenobi]

Hmmm.... not good. Short of a drive failure, the OS should not just disappear like that. If you want to give it a shot, you can try to reinstall following my instructions in this post and see if it works. But I'm skeptical.

I'm thinking you have a bad drive there.

Agreed. Perhaps some other oddity, but the most common reason for the symptoms mentioned would be a failing HD...

UPDATE:

OK....apparently this is a thing. Never seen it myself. Interesting post here and here, with lots of folks claiming the same issue. More technicals if anybody is curious.

 

[iosmike]

Hmmm.... not good. Short of a drive failure, the OS should not just disappear like that. If you want to give it a shot, you can try to reinstall following my instructions in this post and see if it works. But I'm skeptical.

I'm thinking you have a bad drive there.

How are you today? Great news to let you know. I followed your solution and now everything is all right! Thanks again and have a great day!

 

[Weaselboy]

How are you today? Great news to let you know. I followed your solution and now everything is all right! Thanks again and have a great day!

Oh good... I'm still worried about your disk. You might want to make sure you have a good backup in case this takes a bad turn in you.

 

[iosmike]

Oh good... I'm still worried about your disk. You might want to make sure you have a good backup in case this takes a bad turn in you.

Ok, thanks. I have a Time Capsual. I didn't feel it was so important before, but after this time.....