Since making the report, I've also upgraded another machine to 11.10 to 12.04 and calibre still works fine on that one, so it must be something specific to the packages on this machine.. Below is the further detail you requested.
alex@clacks:~$ calibre python2.7: /build/buildd/sip4-4.13.2/siplib/siplib.c:10938: sipEnumType_alloc: Assertion `(((currentType)->td_flags & 0x0007) == 0x0003)' failed. Aborted (core dumped) python-sip: Installed: 4.13.2-1 Candidate: 4.13.2-1 Version table: *** 4.13.2-1 0 500 http://au.archive.ubuntu.com/ubuntu/ precise/main amd64 Packages 100 /var/lib/dpkg/status calibre: Installed: 0.8.38+dfsg-1 Candidate: 0.8.38+dfsg-1 Version table: *** 0.8.38+dfsg-1 0 500 http://au.archive.ubuntu.com/ubuntu/ precise/universe amd64 Packages 100 /var/lib/dpkg/status calibre-bin: Installed: 0.8.38+dfsg-1 Candidate: 0.8.38+dfsg-1 Version table: *** 0.8.38+dfsg-1 0 500 http://au.archive.ubuntu.com/ubuntu/ precise/universe amd64 Packages 100 /var/lib/dpkg/status -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/993652 Title: Calibre crashes on startup after upgrade from 11.10 to 12.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/calibre/+bug/993652/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs