How do you re-purpose or reformat a hd in i-mac?

For a little background, the hd “my passport” is 2 tb and I was using it for the tablo. A while back I had a problem (not with the drive) and did a hard reset on the tablo and I ended up losing 1/2 the drive.
I just purchased a new drive and want to re-purpose the old drive for my I-mac computer. I erased the hd and only 1 tb shows. How do I get the other part back? You can see from the picture, “other” has data which is probably the tablo data. I did a google search and you can’t do a factory reset on the HD.

I just noticed the “other” is only 644 MB, not gb. I guess the other 1/2 is not recognized at all. What do I do?

Your 2GB hard drive currently has a 1TB partition.
The info in the screenshot you posted is related to just that single 1TB partition.

Here are generic steps to be able to use the entire hard drive’s space:
Delete the 1TB partition, and any others that may exist.
Create a 2TB partition.
Format the 2TB partition.

I did delete the 1 tb but my computer doesn’t show that it is partitioned. Also, the little Partition on the top is greyed out, so I doesn’t even let me see or partition even the 1 tb. I’m using El Capitan.

As you can see, it only recognizes 1 tb.

Yeah, you never get what you pay for with a MAC! :smile_cat:


I’ll check it on my PC and see if it still shows 1 tb. I know many IT people who use mac’s at home and love them.
I think the problem is that I need to use linux. But I thought I’d ask first if there was any other way before I go that route.

You’re probably already following the correct steps, but to be sure:

Linux will format properly I’m sure. That’s what I use for Tablo HD formats, backups, restores and such.


What’s the model number of your Western Digital external hard drive?

All I know is it is a “My Passport” from WD. I took a look at it in linux and it still says 1 tb, but it says it has 2 partitions and one is only 100mg. I think it must be corrupted. Thanks for you help.

Have you tried Wester Digital Lifeguard Diagnostics software yet? If not, you might want to.


On a mac you need to unmount the drive… then do a “partition” command…
Just an FYI the Tablo uses a Linux EXT format which the mac can not natively do (nor can a PC without 3rd party software)