Hi.
does anyone know how can i prevent a mikrotik user from resetting RouterBoard and RouterOS?
i make a group without policy in users but the user still can change RouterBoard settings(e.g. enabling reset jumper or boot option).

Check the protected-routerboot setting

https://wiki.mikrotik.com/wiki/Manual:R ... D_settings

Don't give them Winbox, SSH or Telnet access, give them only web access, then with webfig skins you can configure which menu items they can access / see, this way preventing them form rebooting