E: The value 'lucid' is invalid for APT:efault-Release as such a release is not available in the sources
E: _cache->open() failed, please report.
I've been running precise for about 3 months now on x_64. As per above, I upgraded directly from lucid to precise. Most things work as expected. However, whenever I run the Synaptic Package Manager, I get the above error and it closes.
Where is this variable being set?