Resized partition using Disk Utility and lost the data on the preserved partion!

LABachlr

LABachlr

Registered
I was told by Apple that if I used Disk Utility in Leopard to delete one partition and resize another one to take over the amount of space that was gained by deleting the first partition, that no data would be lost. That, however, does not seem to be true, as when I open the resized partition, there is nothing there, yet it says there is only 21.72GB available out of a possible 122.88GB.

The amount of space that is being taken up is the same amount of space that the data was taking up when it was still there. It's still there in some form or another, but is it retrievable, or did Apple give me information that was not correct?

Also, on another forum, I found the another way of merging partitions that I have not tried yet.

It's done in Terminal:

---------------------
diskutil list

that listed back 2 partitions with the identifiers: disk1s1 and disk1s2 (in other cases might be disk0...)

Now,

sudo diskutil mergePartitions "Journaled HFS+" New disk1s1 disk1s2

did the trick (New is the name, it will actually be ignored).

The first partition will be kept intact and the second one will be "merged" therefore you will loose all contents (I made sure it was empty before running the merge just in case).
---------------------------

Can anyone confirm if this works?
 
I just read on the Apple website that yes, you will lose your data when you resize. C'est la vie. Luckily, it's not my only copy.
 
Apple says that you can not resize a partition that has a Master Boot Record, which is in the first sector of the drive. Is it also referring to external drives? Is the first sector the same thing as the first partition?

I did resize the first partition of the external drive, which was a bootable partition, as it had a clone of my hard drive with Tiger before I upgraded to Leopard. Does this partition have an MBR? If so, why was I able to resize it? If not, how am I able to tell if a partition has an MBR?

Apple says to look in Disk Utility, but I didn't see anywhere where it mentioned a partition having an MBR. Even the main drive of my Mac doesn't mention it. But the main drive of my Mac does mention that it is the startup volume and can not be erased (obviously, because I am booting from it). If it can't be erased, then it can't be resized, because when you partition it, you erase it.
 
Just to clarify, which drive have you resized? Only the 1st Partition of your external HD?

I wasn't sure if in your original post you were referencing to an internal drive ... you would need to boot from your Install Disc and run Disc Utility before you could make any partition changes to your internal HD and this would also require you re-install the OS again ...

If your ext hard drive has been FAT32-formatted for PC out of the box. Then this format has an underlying MBR (master boot record) partition-scheme. When re-partitioning a drive in 'Disc Utility', the original partition-scheme sticks, so if you simply re-partition the drive to Mac OS Extended, it will still have an MBR partition scheme... and AFAIK, Macs cannot boot from this ... (please someone correct me if I'm wrong here)

For a Power PC Mac to be able to boot from an external firewire drive, the drive MUST have an APM (Apple Partition Map) Partition Scheme underlying the Mac OS Extended partitions. To do this, click on the 'Options' button in 'Disc Utility' when on the 'Partition' page before partitioning. You will see the options:

GUID Partition Table (for Intel Macs... (note: Power PC's cannot boot from a GPT drive))

Apple Partition Map (to create a bootable drive for a Power PC Mac)

Master Boot Record (to create a bootable PC drive)
​

So.... to make your external drive bootable for your Powerbook G4, choose 'Apple Partition Map' in the 'Options' page prior to partitioning.

AFAIK, an Intel Mac CAN boot from an APM-partitioned drive (this is why the OSX installer can be univerally bootable!), BUT, the problem is that the OSX installer will NOT let you install OSX-intel on an APM-partitioned drive....

You can, however, clone an Intel-Mac-OSX internal drive that has a GPT partition-scheme (using CarbonCopyCloner or SuperDuper) to an external drive with APM, & the Intel Mac will still be able to boot from that clone...

The only real use for doing this, though, is if you want a multi-partitioned backup drive with separate bootable partitions for OSX-PPC & OSX-Intel machines. (Remember that a PPC machine cannot boot from a GTP-partion-scheme drive, hence the need to use APM in this instance seeing as the Partition Scheme applies to the entire drive (it can't be different for each partition.)


I hope this has been helpful ....


.
 
Last edited:
Sorry. Need to specify more.

I have an external drive that had 3 partitions:

The way it was before:

1st partition 111 GB - Bootable copy of my hard drive when I had Tiger; cloned with SuperDuper
2nd partition 10 GB - Extra storage for my data
3rd partition 30 GB - Fresh installation of Leopard

I have since upgraded to Leopard and decided that I would like to use Time Machine instead of SuperDuper backups for now. They say it is best to have an external drive that is larger than your main drive that you are backing up to with Time Machine, as it is always adding new data. The larger your drive, the further back you can go in time.

So, since 10GB is nothing for data, I decided to put that data somewhere else, delete that partition, and resize the partition for the backups to take over the use of that space.

Here is the setup now:

1st partition 122GB - Time Machine backup (have not done the backup yet)
2nd partition 30GB - Fresh install of Tiger

I'm not sure how you tell if you successfully resized the partition, as this is my first time doing it, but the two partitions show up and they both have the correct capacity. The only thing is, on the one that was resized, I did lose the data, but the space is still being taken up by the data that was there. It says that only 21.72GB is available and it has 122.88GB for the capacity.

I will be selecting that as the Time Machine backup drive. Will Time Machine format it when it is selected to be the drive that Time Machine backs up to, or will I have to format it myself via Disk Utility? I'm hoping formatting it will get the space back.

I suppose I could try booting up to the Tiger partition and see if that works.
 
LABachlr, please revisit my previous post as I have heavily edited it to provide more succinct info ... ;) I will read your above post now ...
 
Thanks, Tracy. Yes, it's an Intel Macbook. Should I just try formatting that partition and see what happens? I'll try booting from the Tiger partition now.

I just reread it. Thanks.
 
In Disc Utility select the drive in the left column, by clicking on it then click on the tab marked "Erase" then you can go ahead and partition and that invisible data should be wiped.

Have you seen these pages?

Mac OS X 10.5: About resizing disk partitions

Booting an Intel iMac from an External Drive

FWIW, I just had a look at my own bootable ext HD (Tiger) and note that the Format is Mac OS Extended (Journaled) and the Partition Type is Apple_HFS.

Let me know how it goes with booting from your Tiger clone ...

*EDIT*

I just re-read my first sentence and want to add that doing this would also scrub your fresh Tiger install on that ext drive ...
 
Well, you might not believe this, but when I rebooted and hit the option key, the 1st partition came up as a bootable partition. So, I decided to take a chance and select it. Guess what happened. You bet. Booted right up! It didn't get erased, nor did references to it get wiped. Not sure how booting from it made the data visible again, but it did.

I then tried booting from the Tiger partition. No problem. I checked to see if I could see the data on the 1st partition. No problem. I then booted from the internal drive and looked to see if I could now see the data on the 1st partition. I could! Looks like the partition was successful!

So, Apple is not entirely correct. I'm not sure what happens in other situations where the drive is not bootable, but the data was not affected, aside from disappearing right after I completed the process.

I will now take your advice, erase that partition, and set it up for Time Machine. Thanks.
 
That's fantastic news LABachilr! Did you see my edit in my previous post? If you scrub the partition I'm not 100% sure that your Tiger bootable partition won't also be wiped ...
 
EASEUS Partition Manager claims that it will not damage the data and files as well as no need to reinstall OS and give a 30 days money back gurantee to their customers. I think you can have a try.Hope this is helpful to you:)
 
I had 2 partitions on an external hard drive and ran out of space on the first partition and didn't really need the 2nd. When I tried to follow Mac OS X (Snow Leopard) instructions on merging the partitions using DiskUtility, it wouldn't work because the disk (or the partitions) used the Master Boot Record scheme.

I tried the Terminal solution below and it worked! It merged the two partitions in one in about 5 seconds AND bonus: it preserved the data on the first partition. Of course it erased the data on the 2nd partition but i didn't need it so if you do, transfer what you need first and then run this.

I was on a Macbook Pro running Mac OS X version 10.6.4. Good luck and thanks very much LABacklr!

LABachlr said:
I was told by Apple that if I used Disk Utility in Leopard to delete one partition and resize another one to take over the amount of space that was gained by deleting the first partition, that no data would be lost. That, however, does not seem to be true, as when I open the resized partition, there is nothing there, yet it says there is only 21.72GB available out of a possible 122.88GB.

The amount of space that is being taken up is the same amount of space that the data was taking up when it was still there. It's still there in some form or another, but is it retrievable, or did Apple give me information that was not correct?

Also, on another forum, I found the another way of merging partitions that I have not tried yet.

It's done in Terminal:

---------------------
diskutil list

that listed back 2 partitions with the identifiers: disk1s1 and disk1s2 (in other cases might be disk0...)

Now,

sudo diskutil mergePartitions "Journaled HFS+" New disk1s1 disk1s2

did the trick (New is the name, it will actually be ignored).

The first partition will be kept intact and the second one will be "merged" therefore you will loose all contents (I made sure it was empty before running the merge just in case).
---------------------------

Can anyone confirm if this works?
Click to expand...
 
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