Issue with B&R VNC Viewer – "Please enable loopback adapter" error despite installation

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1

Hi everyone,

I’m facing an issue with B&R VNC Viewer. When I try to connect, I get the error message:
“Please enable loopback adapter.”

I’ve already installed the loopback adapter as suggested, but the error still persists. I’ve tried restarting the system and rechecking the adapter settings, but no luck so far.

Has anyone encountered this before or knows what might be causing it? Any help or suggestions would be greatly appreciated!

Thanks in advance.

2

We use VNC-Viewer since years without any problems. (RealVNC® – Fernzugriffssoftware für Desktop und Mobiltelefon | RealVNC)

3

Screenshot 2025-09-19 113154
Screenshot 2025-09-19 113154383×150 5.49 KB

I am getting this error when i try to open VNC Viewer

4

Couple of questions:

  • what version of VC4 and AS and AR?
  • Connection to ArSim or real hw?
  • anything in the logger?
5

Automation Studio Version V4.3.7.46 SP.
Automation Runtime G4.34.

Visual Components V 4.34.6

Connection for Both Arsim and real Hardware. (As i will be using simulation for some changes and then dump in hardware)
In logger VNC Protocol Error, I have attached the image for your reference.

VNC Server Error
VNC Server Error1356×587 61 KB

6

Ok. In the logger is error VNC Error 28741 with details that VNC server has not started. So this is the reason you have to focus on. Do you have enough memory?

  • try to create empty visu and connect it to VNC server
  • change port of VNC server
7

Thank You for your suggestions, I have Tried Both of the Given Suggestions but still i am getting the same error.

8

The last possible action before you contact local office support is to try a different version of VC. If this does not help either, then please get in contact with the support of your local B&R office and provide a link to this community post as well as the project.

9

Sure ! Thank you for your suggestion