Using the Launcher is currently the only reliable way to manage the ASA 5505 without fighting browser security warnings and deprecated Java versions.
Point the launcher to your Java path. Edit run.bat inside the launcher folder: cisco asa 5505 asdm-idm launcher download
Run show version on your ASA. Match the ASDM version from Cisco’s compatibility matrix. Using the Launcher is currently the only reliable
: Enter your ASA username and password when prompted. If it is a new installation, these may be blank by default. these may be blank by default.