Comment 1 for bug 1816047

Hi Mark,

It seems that you have problem installing and uninstalling due to 3rd party.

Do one thing, run the following commands:

1. ps afx|grep dpkg [To check if this process is running].
2. If there is any process, then kill with sudo killall dpkg
3. Remove the file using sudo rm /var/lib/dpkg/lock-frontend

After this :

1. Go to system settings.
2. Go to Software& Updates.
3. Click on Other Software.
4. Remove all 3rd party repositories.
5. Run sudo apt-get update && sudo apt-get install -f && sudo apt-get update

Then check if you are able to install or uninstall anything.