If you lost or forgot your CA BrightStor ARCserv password, you can do the following to recover it.
Open cmd.exe, and navigate to the root of your ARCserve installation (e.g. C:\Program Files\CA\BrightStor ARCserve Backup\).
Once in the root of the ARCserve folder, type cstop to stop all running ARCserve services.
Use Windows to navigate to the sub-folder \Data\Discovery (e.g. C:\Program Files\CA\BrightStor ARCserve Backup\Data\Discovery). In there, you'll find a folder that bears the name of your server. Rename this folder (e.g. append ".old").
Back in the command prompt, type cstart to start the services again.
Run the command Authsetup /p "password" where "pas ...