I have similar problem with flashplugin-installer and ttf-mscorefonts-installer packages: flashplugin-installer: processing... flashplugin-installer: downloading http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_20161026.1.orig.tar.gz Get:1 http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_20161026.1.orig.tar.gz [27,2 MB] Fetched 27,2 MB in 25s (1.085 kB/s) W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/adobe-flashplugin_20161026.1.orig.tar.gz' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied) Installing from local file /var/lib/update-notifier/package-data-downloads/partial/adobe-flashplugin_20161026.1.orig.tar.gz Flash Plugin installed. ttf-mscorefonts-installer: processing... ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/andale32.exe Get:1 http://downloads.sourceforge.net/corefonts/andale32.exe [198 kB] Fetched 198 kB in 2s (96,3 kB/s) W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/andale32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied) ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/arial32.exe Get:1 http://downloads.sourceforge.net/corefonts/arial32.exe [554 kB] Fetched 554 kB in 2s (248 kB/s) W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/arial32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied) ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/arialb32.exe Get:1 http://downloads.sourceforge.net/corefonts/arialb32.exe [168 kB] Fetched 168 kB in 2s (71,9 kB/s) W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/arialb32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied) ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/comic32.exe Get:1 http://downloads.sourceforge.net/corefonts/comic32.exe [246 kB] Fetched 246 kB in 2s (95,3 kB/s) W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/comic32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied) ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/courie32.exe Get:1 http://downloads.sourceforge.net/corefonts/courie32.exe [646 kB] Fetched 646 kB in 2s (273 kB/s) W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/courie32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied) ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/georgi32.exe Get:1 http://downloads.sourceforge.net/corefonts/georgi32.exe [392 kB] Fetched 392 kB in 1s (233 kB/s) W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/georgi32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied) ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/impact32.exe Get:1 http://downloads.sourceforge.net/corefonts/impact32.exe [173 kB] Fetched 173 kB in 1s (125 kB/s) W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/impact32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied) ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/times32.exe Get:1 http://downloads.sourceforge.net/corefonts/times32.exe [662 kB] Fetched 662 kB in 2s (314 kB/s) W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/times32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied) ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/trebuc32.exe Get:1 http://downloads.sourceforge.net/corefonts/trebuc32.exe [357 kB] Fetched 357 kB in 1s (212 kB/s) W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/trebuc32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied) ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/verdan32.exe Get:1 http://downloads.sourceforge.net/corefonts/verdan32.exe [352 kB] Fetched 352 kB in 1s (248 kB/s) W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/verdan32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied) ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/webdin32.exe Get:1 http://downloads.sourceforge.net/corefonts/webdin32.exe [185 kB] Fetched 185 kB in 1s (137 kB/s) W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/webdin32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied) File permissions: # find /var/lib/update-notifier/package-data-downloads/ -ls 9052762 4 drwxr-xr-x 3 root root 4096 nov 4 10:30 /var/lib/update-notifier/package-data-downloads/ 9047630 0 -rw-r--r-- 1 root root 0 nov 4 10:30 /var/lib/update-notifier/package-data-downloads/flashplugin-installer 9078917 0 -rw-r--r-- 1 root root 0 nov 4 10:27 /var/lib/update-notifier/package-data-downloads/ttf-mscorefonts-installer 9052766 4 drwxr-xr-x 2 root root 4096 nov 4 10:30 /var/lib/update-notifier/package-data-downloads/partial