I was getting the same error message while installing skype on Xubuntu 14.04 amd64. sni-qt:i386 wouldn't install as a result. Jean-Pierre's solution worked for me (although I renamed sni-qt.conf instead of deleting it outright).
-- You received this bug notification because you are a member of Desktop Packages, which is subscribed to sni-qt in Ubuntu. https://bugs.launchpad.net/bugs/1068940 Title: package sni-qt 0.2.6-0ubuntu1 failed to install/upgrade: trying to overwrite shared '/etc/xdg/sni-qt.conf', which is different from other instances of package sni-qt:i386 Status in “sni-qt” package in Ubuntu: Confirmed Bug description: I have no desktop after the upgrade to 12.10 ProblemType: Package DistroRelease: Ubuntu 12.10 Package: sni-qt 0.2.6-0ubuntu1 ProcVersionSignature: Ubuntu 3.5.0-17.28-generic 3.5.5 Uname: Linux 3.5.0-17-generic x86_64 ApportVersion: 2.6.1-0ubuntu3 Architecture: amd64 Date: Fri Oct 19 22:34:48 2012 ErrorMessage: trying to overwrite shared '/etc/xdg/sni-qt.conf', which is different from other instances of package sni-qt:i386 InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012) SourcePackage: sni-qt Title: package sni-qt 0.2.6-0ubuntu1 failed to install/upgrade: trying to overwrite shared '/etc/xdg/sni-qt.conf', which is different from other instances of package sni-qt:i386 UpgradeStatus: Upgraded to quantal on 2012-10-19 (0 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/sni-qt/+bug/1068940/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
