Today I wanted to upgrade my system from Debian Wheezy to Jessie. As first step I thought it is a good idea to upgrade the current wheezy-packages:
sudo apt-get update sudo apt-get upgrade
... however on the "upgrade" command, I got an error (sorry, I only have the text in german):
Paketlisten werden gelesen... Fertig E: Der Wert »stable« ist für APT::Default-Release ungültig, da solch eine Veröffentlichung in den Paketquellen nicht verfügbar ist.
A translation of the error could be:
E: The value "stable" is for APT::Default-Release is invalid, since such a release is not available in the package-sources.