Summary: Today i was facing an issue in my Mozilla Firefox browser due to some script running in back. It causes the system to respond slowly. I gone through the system checking and try to update everything so that to recover if any thing breaking. I found an error while updating the system.
Hash sum mismatch error Ubuntu
I resolved the issue through following simple two steps.
First i removed all the partials repository and then update and upgrade the system it work fine.
sudo rm -R /var/lib/apt/lists/partial/*
And then run the code.
sudo apt-get update && sudo apt-get upgrade
If you still have any issue, feel free to comment here I will guide you further how to resolve.