Let's assume that when you are trying to install apticron the default config file is not created and when you are trying to execute postinst configure the following error message occurs:

Not replacing deleted config file /etc/apticron/apticron.conf

The fix is:

[codesyntax lang="bash"]

aptitude -o DPkg::Options="--force-confmiss" reinstall apticron

[/codesyntax]