In order to back up your HTC mobile data, you must try the beneath steps very carefully:
Just connect your HTC mobile to your system.
Open the HTC Sync Manager >> click on Home
After that, go to Transfer and Backup >> Backup & Restore
Choose the files to back up and tap on the Back up now option.
If you are backing up your data the first time, then choose if to set the password for a backup file or not.