E: Could not get lock /var/lib/apt/lists/lock - open (11: Resource temporarily unavailable) E: Unable to lock directory /var/lib/apt/lists/

This error message typically occurs when another instance of a package manager, such as apt or apt-get, is already running. It means that the package manager is currently locked and cannot be accessed by another process.

To resolve this issue, you can follow these steps:

1. Make sure that you don't have any other package manager or software updater running in the background. You can check this by closing any other terminal windows or software update windows.

2. If you are sure that no other package manager is running, you can remove the lock file manually. Open a terminal and run the following command:

   sudo rm /var/lib/apt/lists/lock

This command will delete the lock file and allow you to run the package manager again.

3. If the above steps don't work, you can try restarting your system. Sometimes, a system reboot can help resolve any lingering issues with the lock file.

After following these steps, you should be able to run the package manager without encountering the "Unable to lock directory" error.