A guide to HTC Backup and HTC Sync Manager
How to backup HTC smartphone
The sync manager needs to open automatically on your PC. If the software is not installed, you can download it manually from the HTC Support page.
Open the Sync Manager, click Music Settings on the left panel, and then select Copy All Music from Phone.
Click Apply and Sync to start the backup.
Click Gallery at the top of the window, then select Import photos and videos from phone automatically.
Repeat steps 3-6 each time you connect your phone to your computer. Alternatively, click the three vertical dots in the top-right corner of the HTC Sync Manager window and select Sync Settings, then select Sync automatically as soon as the phone is connected.
If you're trying to create some extra space on your mobile device, delete photos and videos from the phone after importing to your PC. It removes the media from your HTC One after copying the protection.