How to fix dpkg: warning: ignoring request to remove package-name which isn't installed in APT

First, verify whether the package is actually installed on your system:

dpkg-query --showformat='${Status} ${Package} ${Version}\n' -W package-name

This shows the actual status dpkg has for the package. Common outputs:
- install ok installed - Package is installed
- deinstall ok config-files - Package removed but config files remain
- not-installed - Package doesn't exist in dpkg database

If the output shows "deinstall ok config-files", the package is only partially installed (configuration files remain).

If apt-get fails but you want to remove the package completely, try using dpkg directly:

sudo dpkg --purge package-name

The --purge flag removes the package and its configuration files, which is more forceful than --remove. This often works where apt-get fails due to state mismatches.

Sometimes updating apt's package cache resolves the issue:

sudo apt-get update
sudo apt-get autoremove
sudo apt-get clean

Then try removing the package again:

sudo apt-get remove package-name

If dpkg was interrupted during a previous operation, run:

sudo dpkg --configure -a

This tells dpkg to finish configuring any packages that are in an incomplete state. After this, retry your package removal:

sudo apt-get remove package-name

If the package is in a severely broken state, reinstall it first:

sudo apt-get install --reinstall package-name

Then attempt removal:

sudo apt-get remove package-name

This puts the package back into a known good state before attempting removal.