Hi, >Then I accept this removing. >But then apt-get -t jessie-backports dist-upgrade >Proposed to reinstall libseccomp2 >And so on, the loop should be infinite. complete log? as short answer I would guess: some packages you have installed, in the backport new version gained that new dependency. At the end this is why backports exists, to bring new features and new dependencies. I don't see the error without a log. G.