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Level 1

5 points

Can't erase my Time Machine drive using Disk Utility

Hi.

I've been using an external drive for Time Machine for some time and I want to erase the contents of the drive and reformat it.

When I try to erase the drive using Disk Utilty, something I've done many times on many drives over the years, the Erase Tab is greyed out.

I suspect it might have somehting to do with me encrypting the backup but I can't figure it out. I've also exluded it as a backup drive inside Time Machine Preferences.

Any ideas?

Posted on Mar 13, 2013 8:01 AM

18 replies

Pondini

Level 8

38,863 points

Mar 17, 2013 8:32 PM in response to Pondini

Ah, simpler than I remembered (and it even does it with a USB thumb drive!):

Select the partition (indented), then the Erase tab, and you can Erase it.

If you choose a non-encrypted Format, the drive will be erased and appear normally:

Nov 5, 2013 8:41 AM in response to WhyGuy

Dear WhyGuy, I had a similar problem as a result of trying to repurpose a Time Machine drive that I was using with a different machine. It seems that Time Machine is savvy enough to realize that I am technically not the administrator (since I pulled it from another machine and tried to erase/reformat the drive). In any case after much pondering and trying different unworkable solutions as a result of simply not being able to change the permissions etc. - I came upon what I think is a pretty novel / basic solution.

I simply opened the disk utility and instead of trying to reformat using Mac OS Extended (Journaled), I just used this 3-step super simple process:

1. Open Disk Utiliity

2. Format the subject Time Machine disk with MS DOS (FAT) selected.

3. Then Reformat the drive using Mac OS Extended (Journaled).

It's that simple. No need for repartitioning, special software, mumbo jumbo.

I hope this helps someone else because it took me about 3 hours of looking at obscure shareware and jacking around before it dawned on me that this solution might work.

Kind regards,

BoulderAndrew

WhyGuy Author

Level 1

5 points

Nov 5, 2013 8:49 AM in response to AndrewUnk

Hi Andrew.

Thanks for your reply and it's good to know that's an option. I ended up figuring out how to solve this with my own work around, like you. I think the problem I was facing was that my Time Machine partition was encrypted and this is what was blocking me from reformatting the entire drive. I had to format the disk (extended journaled) without encryption to wipe it clean, then reformat it for time machine. Once that was done I told time machine to encrypt this new blank format. It seems to have worked.

Thanks again for your feedback.

Can't erase my Time Machine drive using Disk Utility