can you please elaborate more about your situation?
did u installed the latest version?
what operating system the master and the clients are using

and what you tried to do that made the error appear?

Yes it is, Reproductile on several pc of brand and different generation

First of all: 4.3.0 is the most recent version while 4.1.2 is a very old version released more than a year ago 😉 And yes, usually you should update both master and client computers. Use silent installation options to automate this task easily: https://docs.veyon.io/en/latest/admin/installation.html#automated-silent-installation

Unfortunately Veyon Master is not capable of filtering computers based on access control rules on the client computers. The reason for this is that the local state of the individual computers (which user is logged on etc.) is not known to Veyon Master so we can't reliably determine whether a certain computer can actually be accessed or not.

You can try to set up https://docs.veyon.io/en/latest/admin/access-control-rules.html and play with the conditions regarding computer locations. This way you can prevent users easily from accessing computers at a different location (room).

Problem solved. Username is Student with no password. A password is not required when using key file authentication. Computer name is used to identify machine.

The upgrade works with a caveat or two. On the Veyon Master machine, it lost all of the location and PC data. Having a .csv file on hand with that info made it almost painless to get them back. The "almost" is due to misinformation in the Veyon-Cli help information:

veyon-cli.exe networkobjects help import

show this as one of the examples:

* Import simple CSV file to a single room: networkobjects import computers.csv location "Room 01" format "%name%;%host%;%mac%"

The above is exactly what I needed to do but it gave an error saying it failed to parse line 1. With no additional info available, I presumed something was wrong with my file... "Does it need a header row?", "Are certain keywords needed in a header row?", and other questions like that came up. After a few experiments, none successful, I noticed the ";"s in the format section of the sample line - changing those to to ","s fixed the problem:

networkobjects import computers.csv location "Room 01" format "%name%,%host%,%mac%"

And for those wondering, a header row in the import file is seen as data, so a new PC is created using the info it contains.

In the old config, I was using keys for authentication. The old keys still work, although I had to configure the Master and Clients to use key file authentication, as they both defaulted to logon auth. As I recall using the old keys may not have been possible back in the 4.1 days, which is what prompted my question here in the first place. It seems that if I'm remembering correctly, that has been addressed and fixed.

So the short answer to my question is "Yes". I hope this helps some else down the road...

~bd

Hi,
It is possible that the italk service in not uninstalled (conflict with veyon service) or another old vnc still running.

@clash Hi,
I do experience the same issue with the standard VNC with windows 7 64bits since veyon 4.2.4 and now 4.3.0.

Thank you