File Transfer Fails on Approximately 500 Windows 11 PCs in Veyon 4.10.4 and 4.11.3

[ahmod333]

Dear Veyon Community Support Team,

I am experiencing a widespread issue with the File Transfer feature in Veyon, affecting approximately 500 Windows 11 computers in our Active Directory domain environment. I would appreciate your assistance in identifying the root cause and finding a reliable solution.

Environment

• Operating System: Windows 11
• Domain Environment: Active Directory domain-joined computers
• Number of affected client PCs: Approximately 500
• Veyon versions tested: 4.10.4 and 4.11.3
• Authentication: Veyon public/private key authentication

Problem Description

File Transfer was working correctly until recently. However, since yesterday, transferred files have stopped appearing on client computers, even though Veyon reports that the transfer has reached 100% completion and displays a green checkmark.

The same issue occurs with both Veyon 4.10.4 and Veyon 4.11.3.

When I select “Transfer and open destination folder,” the destination folder does not open. The transferred files cannot be found in the expected destination directory or by searching the client computer's drive.

Other Veyon features, including remote access and control, continue to work normally.

Troubleshooting Performed

• Tested Veyon versions 4.10.4 and 4.11.3.
• Checked the File Transfer configuration and destination directory.
• Tested both "%HOME%" and a custom destination directory.
• Verified that the destination directory is writable.
• Checked the Veyon service and client-side logs.
• Searched for transferred files on the client computers.

I also found the following error in "VeyonConfigurator.log" on a client computer:

"[ERR] CryptoCore: failed to decrypt password!"

I have not confirmed whether this error is related to the File Transfer issue.

Questions

1. What could cause File Transfer to report 100% completion without the files appearing on client computers?
2. Could this be related to a configuration, service, authentication, or Windows update issue?
3. Are there any known issues affecting File Transfer in Veyon 4.10.4 and 4.11.3?
4. Which diagnostic logs or commands would help identify the root cause?
5. Is there a recommended solution that can be tested on a few client PCs and then deployed centrally to all affected computers?

Since approximately 500 computers are affected, we would prefer a reliable solution that does not require reinstalling Veyon on every PC.

Thank you for your time and support. I look forward to your guidance.

Best regards,
Ahmodullah

[GioeleCalvanese]

We have the same problem with 300 computer, Additionally, the "Start application", "Text Message" and "Open Website" features also don't work.

[GioeleCalvanese]

@ahmod333

Confirming this issue in a school environment.

Environment:

• Windows 11 Pro 26H2 (build 26300.9711)
• Microsoft Defender platform 4.18.26090.9
• Veyon 4.11.x (also tested with latest 4.11.3 – same result)

Symptoms:

• Screen monitoring and remote control work fine
• Text message, open website, file transfer and run program don't work
• veyon-worker.exe is not running; VeyonServer.log repeats every ~5 seconds:
  [ERR] WindowsCoreFunctions: OpenProcess() 0
  [WARN] FeatureWorkerManager: failed to start worker for feature QUuid("{8e997d84-ebb9-430f-8f72-d45d9821963d}")

Observations:

• DefenderSessionHelper.exe runs in the user session and cannot be terminated even by an admin (Access denied).
• A second PC with the identical Windows build and Defender platform (DefenderSessionHelper.exe also running) works fine, so it seems to depend on process enumeration order at logon.
• Running "MpCmdRun.exe -RevertPlatform" fixed the problem immediately (no reboot needed); the text message was delivered right after.

Workaround applied: RevertPlatform + Set-MpPreference -PlatformUpdatesChannel Delayed.