I ran into this when installing an i386 sane backend on a x64 install running "sudo apt-get install --reinstall libsane:i386" fixed the issue.
-- You received this bug notification because you are a member of Desktop Packages, which is subscribed to sane-backends in Ubuntu. https://bugs.launchpad.net/bugs/1533780 Title: package libsane 1.0.25+git20150528-1ubuntu2 [modified: lib/udev/rules.d/40-libsane.rules] failed to install/upgrade: trying to overwrite shared '/lib/udev/rules.d/40-libsane.rules', which is different from other instances of package libsane:i386 Status in sane-backends package in Ubuntu: Confirmed Bug description: sane-backends-extras ProblemType: Package DistroRelease: Ubuntu 15.10 Package: libsane 1.0.25+git20150528-1ubuntu2 [modified: lib/udev/rules.d/40-libsane.rules] ProcVersionSignature: Ubuntu 4.2.0-23.28-generic 4.2.6 Uname: Linux 4.2.0-23-generic x86_64 ApportVersion: 2.19.1-0ubuntu5 Architecture: amd64 Date: Wed Jan 13 23:33:09 2016 DuplicateSignature: package:libsane:1.0.25+git20150528-1ubuntu2 [modified: lib/udev/rules.d/40-libsane.rules]:trying to overwrite shared '/lib/udev/rules.d/40-libsane.rules', which is different from other instances of package libsane:i386 ErrorMessage: trying to overwrite shared '/lib/udev/rules.d/40-libsane.rules', which is different from other instances of package libsane:i386 InstallationDate: Installed on 2015-12-22 (22 days ago) InstallationMedia: Ubuntu 15.10 "Wily Werewolf" - Release amd64 (20151021) RelatedPackageVersions: dpkg 1.18.2ubuntu5.1 apt 1.0.10.2ubuntu1 SourcePackage: sane-backends Title: package libsane 1.0.25+git20150528-1ubuntu2 [modified: lib/udev/rules.d/40-libsane.rules] failed to install/upgrade: trying to overwrite shared '/lib/udev/rules.d/40-libsane.rules', which is different from other instances of package libsane:i386 UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/sane-backends/+bug/1533780/+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