I needed to change the Dynamic DNS (DDNS) host name used by the No-IP DUC 2.2.1 client on a system on which I had installed the client software years ago. The system was on a LAN with a router that had a dynamically assigned external address provided by the company's Internet Service Provider (ISP). I used No-IP's DDNS service to have the system contact a DDNS server provided by No-IP which would note the IP address from which it was contacted and associate that address with a FQDN, e.g., acme.example.com, so that I could connect to the site for troubleshooting without having someone at the site determine what the site's currently assigned IP address might be by going to a site like WhatIsMyIP, which is a site I usually have people go to when I need them to provide me with their current IP address. The No-IP DUC client was running on the system as a system service and the icon for the software was in the notification area, aka the system tray, but I found that the password I thought I had set for it didn't work and I couldn't remember what it might be.
Since it was very late and I was in a hurry to make the change,
I thought I could probably find a registry key where the password
was stored and fix the problem more quickly by blanking out the
contents of that registry key. For DUC 2.2.1, the relevant registry
key, which can be accessed by the Microsoft Windows built-in
which is a REG_SZ key. To remove the tray password, you can
simply double-click on the key and remove the value, which is stored
in encrypted form, associated with it. You can then access the
options for the software without a password. Note: you may only see
this key under
HKLM\SOFTWARE if the DUC client has
been configured to run as a system service. If it isn't look under
To reset the password, click on the No-IP icon in the system tray
and choose Show or double-click on it. Then, click on
Options and, under the Standard tab, check the box for
"Require password to restore window from system tray". The text
associated with that option states "This option will force the DUC
to always start hidden. When you double click the
system tray icon, it will ask for the password below.
The only way to remove this is to uninstall and
reinstall the DUC." But by removing the value from
you can do if you are logged in under the administrator account, you can skip
I don't see being able to remove the password via the registry as a security issue, since doing so requires administrator privileges; it's simply a shortcut that saves the time of reinstalling the software.
Note: the current version of the DUC software, which is 4.0.1
does not store the password at this location. If you configure it
to run as a service, there is a
HKEY_LOCAL_MACHEINE\SOFTWARE\Vitalwerks key will be created
at the time you set the software to run as a service, but there is no
TrayPassword key beneath it.