I have a faulty MBP 17' Late 2009. I can sell it for spares & repairs on ebay for quite a lot as I've found but it has a lot of sensitive data on it and I'd like to return it to a base system.

The problem is that there's a problem with the heatsync and it will switch off without warning if it gets too hot.

What would be the safest method of doing clean install. I have no means of connecting the internal drive to another machine.

Thanks very much.


If the computer had sensitive information on it, you really should perform a secure erase, but in order to do that properly you need to start from something other than the disk you're about to erase. The easiest way to do this is to get an erasable USB flash drive (at least 1GB) as a recovery disk:

  1. Convert the flash drive to GPT partitioning: plug the flash drive in, then run Disk Utility, select the drive from the sidebar (be sure to select the main drive entry, not the volume listed under it), then select the Erase tab, select "Mac OS Extended (Journaled) from the Format pop-up, and erase the drive. When it finishes, make sure the info at the bottom of the window lists "Partition Map Scheme: GUID Partition Table".

  2. Download Apple's Recovery Disk Assistant, and use it to convert the flash drive to an external recovery disk.

  3. Boot from the recovery disk: restart the Mac, and hold down the Option key. It'll display icons for all the bootable volumes it finds. There'll probably be an internal recovery volume as well as the external; you should be able to tell which is which by their icons. Double-click the external recovery disk to start from it.

  4. Once recovery mode starts, run Disk Utility. Select the internal disk from the sidebar (again, the main disk entry, not the volume listed under it). Then select the Erase tab, then click Security Options. In the Secure Erase Options dialog, move the slider one tick to the right (it should say something like "This option writes a single pass of zeroes over the entire disk" under the slider). Dismiss the Security dialog, then click Erase to erase the disk.

    Writing zeroes over the entire disk will take a while. If the computer gets too hot and shuts down partway through you'll wind up with only some of the data erased; I don't know of a good way to continue from where it left off, so you may have to retry from step 3 (and maybe add cooling; see @Dave Nelson's answer).

  5. After it finishes, quit Disk Utility and the use recovery mode's Reinstall option to install a clean copy of OS X.


If overheating is the problem I would try doing the clean install while having a fan blow cool air directly onto the computer into the vent openings. I may even remove the bottom covers to increase airflow.

If you are selling for parts, why not remove the hard drive and sell it drive-less, then take a hammer to the drive itself to protect your data.


If you have another Mac, boot the laptop in Target Disk Mode. Running the disk alone shouldn't heat it up too much. Zero-fill the disk. Then, install a fresh OS.


Since you're selling it for parts anyway, I'd just yank the hard drive and sell it without one.

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