HKLM\Software\OpenVPN
disable_save_passwords
The installer sets it to 0. Change to 1 to disable the feature.
REG ADD "HKLM\Software\OpenVPN" /v "disable_save_passwords" /t REG_DWORD /d 1 /f
HKLM\Software\OpenVPN
disable_save_passwords
REG ADD "HKLM\Software\OpenVPN" /v "disable_save_passwords" /t REG_DWORD /d 1 /f