It's wrong opinion. Restore factory settings cannot represent the phone data is permanently deleted. Today, there are many powerful data recovery software can recover the deleted data in the phone. In order to cope with this recovery software, you can only use a professional delete tool to permanently delete the data. Since your HTC is a Android phone, then you can use the Android Data Eraser to permanently delete all data from HTC in a click.
Android Data Eraser can provide you with a strong cleaning effects. Once you use the software to erase the data in your phone, your phone data will disappear forever, which cannot be found in any way. This is permanent and irreversible. In addition, you only need a few simple steps to permanently delete the phone's data. And the software will provide you with a corresponding tutorial to teach you how to use. More importantly, it can delete photos, contacts, messages, call logs and all private data. Moreover, it supports almost all Android devices in the market. So your HTC can also use the software.
Steps to Permanently Erase All Data & Settings from HTC
Step 1. Run the software and connect the HTC phone
First, download and install Android Data Eraser on your computer. After running it, find "Data Eraser" from the main interface and click on it. Then, use a USB cable to connect your HTC phone to your computer. You also need to open the USB debugging on your computer to make the program smoothly manage your phone.
If the Android os version is above 4.2.2, there will be a pop-up message on your phone asking you to allow USB debugging. Tap on "OK" to continue.
Step 2. Start deleting data from the HTC phone
When the program successfully senses your HTC phone, click "Erase All Data" to start deleting your phone data.
However, when the program enters the next interface, you also need to enter "delete" and click "Erase Now" button to confirm your operation. Once you click "Erase Now", your phone data is officially deleted.
Step 3. Perform Factory Data Reset on Your HTC Phone
When the program to complete the process, you also need to tap on Fatory Data Reset or Erase All Data on the phone. This will help you completely erase all the settings on the phone.
When the main interface appears "Erase Completed", your phone data has been permanently deleted, the entire process is over.
Note: During the whole wiping process, please ensure that the connection between your HTC phone and the computer is normal.