I faced this issue while I was manually uninstalling some packages using synaptic.
I have the feeling that the automatic upgrade checker kicked in after I uninstalled a first bunch of packages, just before I uninstalled additional packages.
Did apt_check.py choke on an APT lock file?
I came the upgrade path Ubuntu 9.10 -> 10.04beta
I faced this issue while I was manually uninstalling some packages using synaptic.
I have the feeling that the automatic upgrade checker kicked in after I uninstalled a first bunch of packages, just before I uninstalled additional packages.
Did apt_check.py choke on an APT lock file?