W: Can't drop privileges for downloading as file '/var/cache/apt/archives/partial/libarchive13_3.2.1-2~ubuntu16.04.1_i386.deb' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied) Reproducible: Always Actual Results: W: Can't drop privileges for downloading as file '/var/cache/apt/archives/partial/libarchive13_3.2.1-2~ubuntu16.04.1_i386.deb' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied) Expected Results: no problems still ongoing issue.
Could you PLEASE report bugs with 'apt' updates to the bug tracker of you distribution?