3TB drive shows up as 1TB (iMac)

Hey Gang,

So this is driving my nuts - I have an iMac with a 3TB drive but it only shows 1TB.. the other two TB show up as "Free Space".

I went into Recovery in an attempt to wipe the entire drive to get it to see the entire 3TB drive, but it won't do anything with it. When I try to format the 2TB partition, it simply flashes a message on the bottom of the window, but does not apply the change.

Would anyone have an idea as to what the issue could be?

Thanks!

Which model iMac do you have?
Which version of OSX?
Did you iMac come with a 3tb drive or have you installed it?
Has it always been 1tb + 2tb or has this happened recently?
Do you have or have you attempted to add a bootcamp partition?
What does the message say?

Did you try using Disk Utility?

mrplow said:

Which model iMac do you have?
Which version of OSX?
Did you iMac come with a 3tb drive or have you installed it?
Has it always been 1tb + 2tb or has this happened recently?
Do you have or have you attempted to add a bootcamp partition?
What does the message say?

Click to expand...

Late 2012
OSX 10.8.4
Yes, came with a 3TB drive
I just found out that one of my colleagues attempted to bootcamp it.. so it was a 3TB drive at one time.

The message says "Preparing to partition disk", it just flashes, however, and does nothing.

louishen said:

Did you try using Disk Utility?

Click to expand...

Indeed..

There was a issue with in OSX prior top 10.8.3 with 3tb and bootcamp but that shouldn't come into play if you're at 10.8.4

Have you tried using the bootcamp assistant again? Bootcamp partitions should only be modified using the bootcamp assistant

Bootcamp only sees the 1TB partition...

Disk Util sees the 2TB "Free Space" partition, but won't let me do anything with it. I'd be ok with reformatting the entire drive and then reinstalling the OS as well, but DU won't alter it..

I went into Recovery in an attempt to wipe the entire drive to get it to see the entire 3TB drive, but it won't do anything with it.

Click to expand...

Did you select the drive itself then erase rather than selecting the partition?

It sounds like the 2tb part isn't partition at all so you should just be able to drag the Mac OS partition to fill the full size of the disk.

See here from 26 seconds onwards

I figured it out...

The 2TB partition was marked as "Free Space" by MAC - I am not sure how it happened, but it must have happened when my colleague tried to bootcamp it.

Disk Util would not permit resizing the disk, or formatting it.. it was just... "useless space".

To solve it:

Selected Windows USB Drive from startup, and then turned the unrecognized partition into a Primary Partition (I could not format it as it was marked GPT). However, from there I booted into Recovery mode and used Disk Util to remove the partition and it automatically turned it back into Mac OS (journaled).

Rebooted the iMac and voila - it is showing a 3TB drive again.

I do have to say that this was cumbersome; Disk Util saw the partition as "Free Space" yes was not able to manipulate it.

Thanks for trying to help guys!

Sounds as thought the bootcamp assistant was interrupted before completing and left the partition in an inconsistent state.

Glad you got it sorted.