If you lost or forgot your CA BrightStor ARCserv password, you can do the following to recover it.

1. Open cmd.exe, and navigate to the root of your ARCserve installation (e.g. C:\Program Files\CA\BrightStor ARCserve Backup\).
2. Once in the root of the ARCserve folder, type cstop to stop all running ARCserve services.
3. 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").
4. Back in the command prompt, type cstart to start the services again.
5. Run the command Authsetup /p "password" where "password" is the password you wish the new password to be. This command runs for awhile and will give some errors which you can ignore.
6. The password will be reset and you should be able to log in with caroot and the new password.

Source: TEC409645
Has been tested on ARCserve r11.5.