Hi, yesterday I had a unknown problem with my synaptic. I looked after different solutions but none matched nor helped me. Then I went for the command line installation. And I saw that there was the problem reading “lock” file located at “/var/lib/apt/lists/lock”. To fix this problem please follow the steps below.
1) Fire up your terminal and type “sudo rm /var/lib/apt/lists/lock”
2) Type you password and press Enter
Now the file is removed and you will find that your problem has been solved.