1. Go to "wp-content/plugins".
2. Open the file "bp-custom.php" ( if you didn't find it just create a new one ).
3. Paste the code in the page below :
https://gist.github.com/KaineLabs/084784adb05a6f047677f9113764ffc5#file-yzc_reset_widgets-php
4. Refresh your browser twice on Profile Structure settings
5. Once you see the widgets has been reset successfully, please remove the snippet.