ImunifyAV uninstallation failed with 'imunify-antivirus package pre-removal script subprocess returned error'

Issue

ImunifyAV cannot be uninstalled because of the following transaction error:

WARNING: Free license can not be unregistered
dpkg: error processing package imunify-antivirus (--remove):
installed imunify-antivirus package pre-removal script subprocess returned error exit status 3
dpkg: too many errors, stopping
Errors were encountered while processing:
imunify-antivirus
Processing was halted because there were too many errors.
E: Sub-process /usr/bin/dpkg returned an error code (1)

Environment

• ImunifyAV
• Ubuntu

Solution

1. Comment out the line in /var/lib/dpkg/info/imunify-antivirus.prerm where the unregister command was supposed to be executed like below:

 # /usr/bin/imunify360-agent --console-log-level=WARNING unregister

2. Run the package uninstallation again:

apt-get remove imunify*

Cause

The package manager could not remove the package because the /var/lib/dpkg/info/imunify-antivirus.prerm script returned an error because the agent was not registered on this server and thus, the unregistering procedure failed.

Useful links

• https://docs.imunifyav.com/imunifyav/#uninstall.
• https://serverfault.com/questions/894878/subprocess-installed-pre-removal-script-returned-error-exit-status-5.