Selling a computer, smartphone or tablet should be as easy as wiping all your personal data off of it and handing it over to the buyer, but sometimes there are little hidden authentication tricks you might forget about. From iTunes to the Kindle app, here's everything you need to deauthenticate before you sell your device.
We've walked you through how to securely wipe your phone and computer before, but some apps also authenticate DRM and serial numbers with your computer directly. If you don't deauthenticate, sometimes you either lose access to the app, or more annoying, the buyer can't set up their own account.
Of course, this isn't only applicable to selling your device. Even if you're just reinstalling the OS, you'll want to deactivate this software before you do. Otherwise, you might be stuck trying to dig up old serial numbers and calling customer support just to access the software you already own.
Adobe Creative Suite: If you still have the Creative Suite installed and you have access to your computer, you need to open up each app and select Help > Deactivate. This will unlink your Adobe account from your computer so you can reinstall it on a new one.
Dashlane: As a password manager, Dashlane is fairly particular about which devices get access to your account. Head to the My Devices tab and disable the device you're selling.
Dropbox: If you've securely wiped your hard drive, there's no reason why anyone should be able to access your Dropbox account, but it's better to be safe than sorry. So, before you sell it, unlink your computer so it doesn't have access anymore.
Google Play Music: Google Play Music lets you listen to music on 10 different devices, which seems like plenty, but if still good to deauthorise your devices when you sell them. The process for each device is pretty easy.
Google App-Specific Passwords: If you're using Google's two-factor authentication (and you should be), then you're probably already familiar with application-specific passwords. These passwords are specific to a single application on a single device. There's no reason why someone should have access to these after you sell a device, but it's still good to clean things up. Head to your App Passwords page and click the "Revoke" button for any apps on your old hardware.
iTunes: iTunes only lets you play music and videos on up to five devices, so it's good to deauthorise your computer before you sell it. Just open up iTunes, click Store > Deauthorize Computer, and select "Deauthorize Computer for Apple Account."
Kindle App: The Kindle app is linked to your device, which means it's linked to your computer, iPad, iPhone, Android phone or wherever else you have it installed. You can always add new devices, but the person who buys your old device can't add their own until you deregister the Kindle app. Head to the Manage Your Content and Devices section on Amazon, and click the "Deregister" button on your old device before you sell it (the same goes for Kindle hardware).
Microsoft Office: You can install Office on five different devices, so it's a good idea to reactivate any devices you sell. Just head to your account page, click "Install Information" and select "Deactivate Install."
Any additions to this list? Tell us in the comments.