Does resizing partition actually erase it, unlike what Disk Utility explicitly says?

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Folks-

Sorry for a lame first post. I'm a long-time Apple user trying to get back into the swing of things after five or so years of letting everything pass me by.

I recently bought 10.7 and wanted to make a bootable external HD for troubleshooting purposes. I figured Apple's own Recovery Disk Assistant would be fine.

On its 'about' page, they state:

"The Lion Recovery Disk Assistant will erase all data on the external drive when creating the Recovery HD. You should either backup your data before running the Lion Recovery Disk Assistant, or create a new partition on the external drive."

So I went to do this. I admit that I could stand to have a far better command of this stuff.

With my external HD plugged in, I went into Disk Utility, selected the disk, and then selected the 'partition' tab. There was nothing about creating a new partition without deleting my old one. Tragically, I missed the '+' symbol as the step necessary to create a new partition.

But here's the kicker: Disk Utility says "to resize a partition on the selected disk, drag its resize control and click apply. The size of the partition will change, but the partition won't be erased." Stupidly, I resized the window of which a decade of my crucial data was represented as a blue fraction, and clicked apply. One second later, the operation was complete, and my external HD was erased.

Two questions:

(1) why is there language about a partition not being erased when resized if it indeed is?

(2) judging from the single second this disaster took to unfold, DU did not write-over my disk, just deleted the index or some such thing. How screwed am I?

Profusest thanks for any help or input other than that pointing out my folly.


EDIT: apparently "unlike what Disk Utility dangerously implies" would have been a better choice of words.
EDIT 2: anybody know of 'undelete' software that can recover files with their original names?
 

chscag

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(1) why is there language about a partition not being erased when resized if it indeed is?

First and foremost: Whenever you do anything to a hard drive that may endanger its data, a backup should be made. Sorry to mention it but it's worth repeating so others can learn from this.

The partition wasn't erased, it was your data that has been put in "la la" land because it's no longer associated with the partition. The reason being is you resized it and therefore changed the partition table.

(2) judging from the single second this disaster took to unfold, DU did not write-over my disk, just deleted the index or some such thing. How screwed am I?

You're correct. The partition map has changed but your data still exists but it can't be retrieved because it's no longer associated with the partition.

Profusest thanks for any help or input other than that pointing out my folly.

EDIT 2: anybody know of 'undelete' software that can recover files with their original names?

Recovery software is not inexpensive, however, if your data is important then it will be worth the cost to you. Having said that, I recommend Data Rescue 3 from Prosoft. You might wish to download their trial version first before paying for the full version.

Let us know.
 
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Thanks for responding. At this point I'm pretty bummed. Because all of the undeleted files' names and organizational order are lost, it's almost no consolation to be able to "recover" them. If it took me only 5 seconds to open and re-name each file, which is a silly estimate when things like figuring out file organization relative to other files are considered, it would still take me 525 hours straight.

Another bummer: I have no doubt Data Rescue 3 is superior, but I already plunked down $100 for MacKeeper undelete software last summer, and it is excruciatingly slow. In three hours, it has scanned only one tenth of the drive.

I'm really quite bitter about the nature of the language in that Disk Utility window. The 'partition' section in Disk Utility has a resizable white window representing an existing partition. In this window, existing data on the partition is represented by a blue area proportional to the space used by the data. To re-size a partition, one re-sizes this window from the bottom-right corner in a way that the blue area remains enclosed (i.e. data unaffected) by the re-sizing. Worse still, it explicitly states:
"to resize a partition on the selected disk, drag its resize control and click apply. The size of the partition will change, but the partition won't be erased."
Apparently they mean that the partition itself won't be deleted, which would be an odd enough thing to say, but this follows their use of the word "erase" meaning 'erase data' one paragraph earlier. Clicking 'apply' does not set off any alarms in the form of red triangles containing exclamation marks. Nothing of the sort. It's surreal.

Anyway thanks again for responding.
 
C

chas_m

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Get rid of that MacKeeper as quickly as you can. You've been snookered.

Sooooo many threads, warnings and problems associated with MacKeeper on this forum. Do a search.
 

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