For me, this solved the problem:
apt-get clean
This basically deletes all the downloaded ".deb" files (which are no longer needed after they have been installed), which has the added advantage of freeing up some disk space.
For me, this solved the problem:
apt-get clean
This basically deletes all the downloaded ".deb" files (which are no longer needed after they have been installed), which has the added advantage of freeing up some disk space.