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Practical Computer Advice
from Martin Kadansky
Volume 9 Issue 6
June 2015
Disposing of a Computer or Phone or Tablet? Don't Give Away Your Personal Data as Well!

Are you about to sell, give away, donate, or dispose of a computer, smartphone, tablet, answering machine or other technology? If that device contains any personal or private information, you may be putting your privacy or security at risk, even if the device doesn't work anymore.

The problem
Over time, almost any technology that you use will accumulate valuable data about you, your activities, your interests, your family, your business and more. Since all technology eventually wears out or stops working, or becomes less useful to you or obsolete, you will discard it at some point. What happens then to your data that's still stored in that device? Will some stranger be able to extract it and make use of it without your knowledge or consent? How can you protect yourself and prevent that from happening?

Here are the two most common general solutions to this problem. Before getting rid of your unwanted device, you should either:
  • Erase it, using a thorough and secure method, usually using special software or the device's built-in "factory reset" or "erase" function, or
  • Physically destroy it (or just its internal storage), using a hammer, pliers, scissors, or (if appropriate) a powerful magnet.
If you don't know how (or don't want to do this yourself), I recommend keeping the device until you can do it, or until someone you trust can do it for you.

Your computer
The biggest example of this problem is when you replace your computer, where you probably have accumulated years of documents, photos, email addresses, email messages, appointments, passwords, business records, personal and family records, medical and financial information and more on the internal hard drive. You may also have passwords or special software on your computer that give you access to data stored on other computers or the internet.

First, you should thoroughly verify that all of your data and software are set up and working properly on your new computer.

Then, when you're ready to dispose of your old computer, your goal is not only to remove your data, but also to remove any implicit access to your online data, including access to any email accounts, online storage, and any other internet accounts. However, given the many ways computers can remember your web sites, usernames, passwords and more, it's just not practical to try to remove all of this brick by brick. Instead, here are the best "bulldozer" approaches I've used:
  • Completely and securely erase your computer's entire internal hard drive(s) using special software. This will wipe everything (except what's stored on the motherboard) - Your data, software, and the operating system, and make the computer unusable. Then, anyone who wants to use the computer will have to reinstall the operating system.
  • Remove the computer's internal hard drive(s) and physically destroy them. Anyone who wants to use the computer will have to install another internal hard drive, and will probably also have to reinstall the operating system as well.
  • Create a new computer user, delete all other users (and uninstall any special software), then securely erase the hard drive's free space. This approach is occasionally useful for an older computer (especially a laptop) with a customized operating system whose original system disks are missing and difficult to replace, so reinstalling the right operating system won't be possible.
What if your computer still works, and you want to securely remove your data and give it to a friend or donate it to a worthy organization, but in a condition where they can start using it right away? I recommend doing all the work up front (or having someone you trust do it for you): Erase it using one of the methods above, then fully prepare it for re-use.

Other examples
Similarly, other devices you're about to discard should be "cleaned" (securely erased or factory reset) or destroyed first. Here are some examples of devices, the data they might store, and (if they still work) how to erase them:
  • Are you going to have your computer's internal drive replaced or upgraded? The old drive should be securely erased or destroyed before being discarded. Talk to your computer person before the work begins to confirm who will do the erasing or destroying. Some shops don't erase anything, so be sure they agree to give you the old internal drive back so you can then have it erased or destroyed.
  • Cell phones, smartphones, and tablets: They stored lots of interesting data about you - Lists of calls you've made and received, text messages, contacts, photos, and access to your email and other online accounts and more; use "factory reset." I bought a used cell phone on eBay once and found the previous user's phone numbers, appointments, and photos of their children.
  • Old computer backup disks: "Deleting" files doesn't protect your data from someone who knows how to "undelete"; instead, securely erase or physically destroy them.
  • Digital cameras and any loose camera cards: The probably have photos of you or your family on their internal cards; copy any photos to your computer, then securely erase or physically destroy the cards.
  • Flash drives or "thumb drives" or keychain drives; copy any important data to your computer first, then securely erase or physically destroy them.
  • GPS devices: They store the street addresses you've driven to recently, and places you've marked as "favorites"; use "factory reset."
  • Answering machine: Your greeting and incoming messages may reveal personal information about you; erase them.
  • Desk phone or Fax machine: They store the most recent number(s) you've dialed, caller id information on calls you've received, and speed-dial numbers you may have programmed into them; erase them or use "factory reset."
  • Digital photocopiers: These have internal hard drives (just like a computer), and your unit might be set to retain copies of everything you've ever copied. Even if your unit is set to delete after copying, a thief could use special software to recover recently deleted images from the internal drive. Find out how to erase it before discarding.
  • Multifunction printer/fax/copier/scanner: Some models may store recent faxes in memory. After learning about this, I was surprised to discover that my HP OfficeJet J6480 stores up to 8 recently received faxes in its RAM (it has no internal hard drive), which are easily reprinted later using "Reprint Faxes in Memory" on its Tools menu. These are deleted when you turn off the power using the Power button or choosing "Clear Fax Log" from the Tools menu (and presumably also by "Restore Factory Defaults"), but they are not deleted when you unplug the power cable! Erase them periodically, as well as before discarding.
  • CDs and DVDs: Some shredders can handle them, just be sure not to put the shreds in with your paper recycling. Or, you can cut them into 2-3 pieces with scissors, or break them with your hands. Just be careful to do this holding the CDs deep inside a trash can or trash bag because they may shatter, exploding into lots of very sharp tiny pieces. Yes, I did this once, years ago, and I'm still finding sharp shiny CD shards in the rug around my desk.
  • Floppy disks, Zip disks: Break open the plastic shell (which probably isn't recyclable), catch the shutter's metal spring that may bounce out, then use scissors to cut up the soft ("floppy") magnetic-coated plastic disk inside.
Note that different manufacturers use different terms for "factory reset": "hard reset," "hard reboot," "master reset," "restore to factory settings," etc.

  • Don't jeopardize your privacy or give away your personal information or risk identity theft when you dispose of your computer or other technology.
  • Just like you would shred important paper documents before putting them in the trash or recycling, for every piece of technology you're going to discard, ask yourself if there was ever any important data on it. If so, or even if you're not sure, don't get rid of that device until it has been thoroughly erased or physically destroyed.
  • Remember that just because you may not be able to power on or operate the device anymore, a thief or scavenger who gets their hands on it may be clever enough to take it apart, remove its internal storage, and use other equipment to gain access to your valuable data. Don't make the mistake of assuming that a "dead" device no longer has your data inside!
Where to go from here
How to contact me:
email: martin@kadansky.com
phone: (617) 484-6657
web: http://www.kadansky.com

On a regular basis I write about real issues faced by typical computer users. To subscribe to this newsletter, please send an email to martin@kadansky.com and I'll add you to the list, or visit http://www.kadansky.com/newsletter

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Copyright (C) 2015 Kadansky Consulting, Inc. All rights reserved.

I love helping people learn how to use their computers better! Like a "computer driving instructor," I work 1-on-1 with small business owners and individuals to help them find a more productive and successful relationship with their computers and other high-tech gadgets.

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