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If you see an error message like this in Wireshark:
this is because your current user doesn’t have permission to capture packets from your network card.
This can be the case even if you have selected to allow normal users to capture packets during the Wireshark installation process. This is because the setting only takes effect after logging out and logging back in (or rebooting).
To fix the issue temporarily without logging out, run Wireshark as root: sudo wireshark
In order to fix the issue permanently, ensure your user is added to the wireshark group:
sudo usermod -a -G wireshark $USER
and then log out and log back in again (or reboot your computer).