Windows 11 2022-08 Updates Broke Veeam Agent - Solved

[andya]

SOLVED! I first submitted the ticket to Veeam Support, Case #05617641. Then I found the fix. I am posting it here because it appears to be a generalized issue that will affect other users who update Windows 11.

After the Windows 11 2022-08 updates (KB 5016629 and KB5016691), Veeam Agent for Microsoft Windows failed to open, throwing this error dialog:
Veeam.Setup.Endpoint.dat - Application Error
The application was unable to start correctly (0xx0000135).
Click OK to close the application.

For some reason, after the Windows 11 updates, .NET 3.5 was disabled.

SOLUTION: .NET 3.5 is required to run an already-installed Veeam Agent for Microsoft Windows. .NET 3.5 is also required to install Veeam Agent for Microsoft Windows on Windows 11 after the 2022-08 updates.

To enable .NET 3.5:

In the Windows Search box, type: Turn Windows Features On or Off
Check the box beside .NET Framework 3.5 (includes .NET 2.0 and 3.0)
Restart the computer.

[HannesK]

Hello,
and welcome to the forums.

Thanks for sharing the solution. I checked support cases for KB5016629, KB5016691 and 0x[x]0000135 and got zero hits for that. Not sure how often the situation you ran into really happens.

Best regards,
Hannes

[andya]

UPDATE: The issue appears to be **specific to some pre-installed versions of Windows 11** shipped on new computers. Windows 11 works fine ... until you apply updates. Then various Windows components are disabled. Enabling them resolved the issues. So this is not a Veeam issue, though Veeam Agent for Microsoft Windows was impacted by it.

[Dima P.]

Hello Andy,

Thank you for sharing the details. Can you please clarify what pre-installed components were causing this? I assume newer versions of .Net? Thanks!