Just live with the warnings until somebody fixes them. Or give _apt rwx access to /var/lib/update-notifier/package-data-downloads/partial, that's safe. It's not like you get hundreds of them each day.
Just live with the warnings until somebody fixes them. Or give _apt rwx access to /var/lib/ update- notifier/ package- data-downloads/ partial, that's safe. It's not like you get hundreds of them each day.