Comment 20 for bug 1543280

Thanks for this nice workaround, John, but I would strongly suggest not to execute that first line. If you have already, set the permissions back to 755. Instead, the better way to fix this permission problem is the following line:

sudo chown _apt /var/lib/update-notifier/package-data-downloads/partial/

May I at this point also say that the continued existence of this trivial bug is a disgrace and a reason for me to question if there are structural problems within the core Ubuntu development community that may easily lead to more serious problems.