noVNC error: Incomplete zlib block for interactive desktop sessions


Some users are getting the ‘incomplete zlib block’ error when using interactive desktop. desktop is a Nvidia GPU server running Rocky Linux 8.8. ood version is 3.

the issue appears when the user double clicks something within the session. the error is persistent and stays on the screen but the interactive session keeps working.

From the error, I could find that error originates from the following file:

But I couldn’t understand the reason behind it.
not sure what else information I need to provide. please let me know of any potential resolutions.


I’m not entirely sure what could cause this - I don’t think I’ve ever seen it before. The upstream project [1] has no issue for the same, suggesting they’ve never seen it.

I’d wonder if there is anything relevant in vnc.log. You can find it here in the session’s directory.

  1. GitHub - novnc/noVNC: VNC client web application

Hi, thanks for the response. Upon further investigation, the issue seems to be related to some firefox browsers of some users. Other users seems to be using firefox just fine and couldn’t reproduce the issue. In summary, it appears to be a browser issue than an OOD issue. thanks for the help.