How do I completely hard factory reset my HTC ONE?

Note: A hard reset should only be performed after all other troubleshooting options have been exhausted or if you want to remove everything from your unit at the same time.

A hard reset removes all information from your device and returns it to a state just like it has never been used before. All contacts, messages, emails, 3rd party applications, etc. will need to be reinstalled after performing a hard reset.

To perform a hard reset, from the Home screen, press Menu and tap Settings > Privacy > Factory data reset. Follow the on-screen prompts to complete. This process will take 5-10 minutes.

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To perform a hard reset using the device keys:

1. Turn off your phone
2. Press and hold the volume down button (located on the right side panel), and then press the Power button
3. When the display turns on, (when it appear three android images) release the volume down button
4. Use the volume buttons to select CLEAR STORAGE, and then press the Power button
5. All data will be deleted from your phone

Performing a factory reset using hardware buttons

1. Press and hold the VOLUME DOWN button, and then press and hold the POWER button.
2. Wait for the screen with the three Android images to appear, and then release the POWER and VOLUME DOWN buttons.
3. Press VOLUME DOWN to select FACTORY RESET, and then press the POWER button.

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Htc One hard reset

First of all, realize EVERYTHING will be completely wiped out and reset. If that is indeed your goal, I found what looks like the ideal page for you direct from HTC at the link below:

http://www.htc.com/us/support/htc-evo-4g-lte-sprint/howto/393860.html
Resetting HTCEVO4GLTE Hard reset

Performing a factory reset using hardware buttons
If you can't turn HTC One V on or access settings, you can still perform a factory reset by using the hardware buttons on HTC One V.
1. Press and hold the VOLUME DOWN button, and then press and hold the POWER button.
2. Wait for the screen with the three Android images to appear, and then release the POWER and VOLUME DOWN buttons.
3. Press VOLUME DOWN to select FACTORY RESET, and then press the POWER button.
[img title="unlock HTC ONE V hard reset forgotten password" alt="HTC ONE V hard reset" src="http://www.hard-reset.com/images/htc_one_v_hard_reset.jpg" height="350" width="180">
will remove any applications you've downloaded and installed. Be sure to back up
any data and files you want to keep before you do a factory reset.
Performing a factory reset from settings
1. Slide the Notifications panel open, and then tap Settings.
2. Tap Storage > Factory data reset.
3. Tap Reset phone, and then tap Erase everything.Performing a factory reset via settings
The most convenient way to do a factory reset is via the settings.
1. From the Home screen, press MENU, and then tap Settings.
2. Tap SD & phone storage > Factory data reset.
3. Tap Reset phone, and then tap Erase everything.

HTC One V not responding?
If HTC One V frozen and does not respond when you touch the screen or press the buttons, you can still restart it by press and hold the POWER button for at least 10 seconds, and then release it. HTC One V then restarts.

yes 1. Power the phone off.

2. Press and hold Volume Down and Power.

3. Keep holding both buttons until you see the Android logos appear on the screen.

4. Use the Volume Down button to toggle the selection and highlight Factory Reset.

5. Use the Power button to choose Factory Reset.

The HTC Inspire 4G will then complete the hard reset process. SD card data like music and photos should be preserved.
Software method

If you can boot into the device, you can use this option.

1. Tap the application slider and select the Settings app.

2. Select SD & phone storage.

3. Choose Factory data reset.

4. Select Reset phone.

5. Select Erase everything.

The only thing you can do is reset the phone to factory specs, unfortunately, you'll lose your data if not already backed up. Follow this procedure:

What does a Hard Reset do and how is it performed?

A hard reset removes all information from your device and returns it to a state just like it has never been used before. All contacts, messages, emails, 3rd party applications, etc. will need to be reinstalled after performing a hard reset. To perform a hard reset, from the Home screen tap Menu > Settings > SD & phone storage > Factory data reset. Follow the on-screen prompts to complete. This process will take 5-10 minutes

src: http://www.htc.com/us/support/t-mobile-mytouch-4g/help/general-and-other

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