UltraVNC Server asking for password after 24H2 cumulative update

[jlaciad]

Hi,

We are facing a strange issue on only a few computer Windows 11 computers after the install of the 24H2 cumulative update. For an unknown reason, an error message saying that the server does not have a valid password enabled. Before the update, we could correctly connect on those systems without any issues.

SYMPTOMS:
- The issue occurs after the cumulative update Windows 11 24H2 is installed and a system reboot
- The error message appears on the Viewer side while he is trying to connect ("Failed to connect to server XXXXXX. This server does not have valid password enabled[...]")

CONFIGURATIONS:
- UltraVNC 1.4.20
- UltraVNC Server is installed as a Service
- The files are located under "C:\Program Files\customdirectory"
- The configuration of the Server is based on the "ultravnc.ini" file
- "VNC Password" and "View-Only Password" are defined in the ultravnc.ini file (and not visible in plain text)
- The "ultravnc.ini" file is correctly edited if we modify a setting using the GUI (uvnc_settings.exe)
- The "ultravnc.ini" file is the same for all our systems.
- The systems are members of an Active Directory and we use the ACL with AD groups to determine who can connect
- We do install the program since years with a custom batch script (used on all systems) for a silent and automated install and it does work well

TESTS:
- Rebooting UltraVNC Service and Windows 11 system -> Issue persists
- Trying to uninstall completely the app using "add or remove programs" of Windows and reinstall the program afterwards with our script -> Issue persists
- Cleaning registry keys and leftover files within "C:\Program Files\customdirectory" after uninstall -> Issue persists

WORKAROUND:
- The only way, we could resolve this issue is reinstalling completely the Windows system, which is not a very light solution

We know that we are not using the latest version available but because it is only happening on a few machines (like 10 or 20 on a more than > 2000 PCs) we would like to see if there is not something we can do to resolve this issue without reinstalling systems.

We suspect something remaining somewhere on the faulty systems, but we cannot identify what is it, as we have cleaned the installation folders and the registry as well...

Thank you very much for your support.