Authentication rejected

[Saul1]

Hello,
When I start UltraVNC Viewer and enter the password, I always get an "Authentication rejected" message. I entered "sp1" as the password.
Is that not a valid password, or is it too short?
Wolfgang

[artiecon]

I am trying to move from RealVNC, which I use to use with their free licence, but now they want $99USD per year for a minimum connection, to this product. I have the same problem as the user posted on the 7th of Mar of this year.

I have discovered that if the server computer is restarted, the password gets reset somehow. If the server computer is shut down and started, the password still works.

However, operating this was is impossible if the server computer is remote. Luckily, mine is accessible with difficulty.

But needing to change the password every time the computer is rebooted is a showstopper. Does anyone know whay this is happening, and how to fix it?
v 1.6.4.0

Rick

[RudiDeVos]

The password is saved in ultravnc.ini.

For 1.6.4.0:
Sometimes write permission can block writing to password to the file
Copy UltraVNC Server (winvnc.exe) to a temporary folder
Run UltraVNC Server as Application
Set a password, and other settings that you want
This create a new .ini file in the temporary folder
Copy the .ini file into %ProgramFiles% where UltraVNC is installed

For 1.8.x (with Windows respected standard rules):
Running as Service: It is saved in %ProgramData%\UltraVNC
As Application and Standard user: It is saved in %AppData%\UltraVNC, each user has it own password
When you open the "UltraVNC Server Settings", the caption shows also the path of the .ini file
Verify if the password is indeed saved (file has changed time)
If %ProgramData% does not save it, configure it as Application and copy file to %ProgramData%

[ruckb]

i have the same issue.
i can not tell when i encountered it exactly (e. g. which version, which PC, ..) , but first attempt was to install 1.8.2.2. on both sides Client and server, but this did not help.
later i saw 1.8.2.4 and tried again, with a uninstall, reboot, reinstall on both sides, no change.
i have from my main PC a connection to another system that runs windows 10 embedded. i have 1.4.3.6 installed on this one. Connnection here works.
i tried to downgrade all versions to 1.4.3.6, no change.
my .ini file changes if i change the password. there are two .ini files: one in the programm directory, one in programm data. the one in programm data only contains the password hahes, no other data. I ensured both have the same hash as the one in the programm directory. no change
i do not find a winvnc.log in my programm directory of the Server pc, only a mslogon.log that says
19/06/2026 08:12:23 Connection received from xxx.xxx.xxx.xxx
19/06/2026 08:12:27 Invalid attempt from client xxx.xxx.xxx.xxx
MSlogon is currently disabled
Most trials i did was with UVNC running as service, not as application, but if i tried running it as application this did not make a difference.
interesting. i just disconnected my connection to the working system and wanted to reconnect, now i get a "Failed to connect to server !".
so a different message, and main difference.. it takes some time until this message pops up, while the "authentication rejected" pops up immediately.

i disabled the firewalls on both computers for most of the tests.

currently i have no idea what to do next in order to get it working again..

thanks for any input..

Hermann