How Do I Unlock a Disk Drive?

[The Jeep]

Hi - well, my new Yosmite install is not going without a few hickups! I have my old 'main' drive in Slot 1 of my Mac Pro 5,1 running Mountain Lion OSX 10.8 and my newly installed Yosemite in a new 2TB drive in Slot 2.

I have also installed a 4TB drive for Time machine backup of both systems, so I realise now I should've partitioned that drive from the start. Instead I just formatted it and started a Backup while in OSX 10.8. I then rebooted in 10.10 and went into disk utility and tried to partition my backup drive there. For some reason it didn't work so I went ahead and erased the disk expecting to be able to start over. But no, it now seems the disk is 'locked'.

I then went into Time Machine in 10.8 and removed that disk as backup disk and did likewise in 10.10. Now the drive doesn't show up in 'My Computer".

In Disk Utility it appears with only 'First Aid' and 'Partition' options available. I First Aid I can verify and repair the disk but it comes out squeaky clean, with no errors. In Partition all the controls are greyed out and I can do nothing. In OSX 10.8 at least it lets me know that the disk is locked.

So, how do I unlock a disk drive that I've locked through cocking around? There must be a way, Shirley!

 

[MacInWin]

I'm running Yosemite, so DU may have changed, but the controls on all my drives are greyed out until I change the partition layout. That un-greys the Name, Format and Size blocks. Have you done that?

 

[The Jeep]

Thanks Jake. Somehow I managed to lock the drive with some kind of security setting (GPT?). From a tip inline I went into Terminal/diskutil and managed to erase/reformat (can't remember exactly) and then got access to the drive again in DU.

 

[MacInWin]

Glad you got it sorted. Well done!