Jupyter Lab not opening more than one file

[ArijitSinghEDA]

I am using jupyter lab, and when I try to open an .ipynb file, I get the following warning:

I have closed and opened my jupyter lab multiple times, I have even upgraded from v4.0,4 to v4.0.8. Anyone who can help me this?

P.S. I have not used --collaborative flag while starting my Jupyter lab, but it is still showing RTC when it opens in my browser.

[krassowski]

To disable RTC in 4.0 you need to uninstall jupyter_collaboration - the --collabrative flag is no-op. The configuration is handled on the other side too: https://jupyterlab-realtime-collaboration.readthedocs.io/en/latest/configuration.html