Using the proposed libical does not appear to fix the issue. Updating to evolution-data-server_2.26.1-0ubuntu2 (from the proposed) allowed the appointment to be moved (and quite quickly). It may be possible that it was the both of them working together.
-- Updating calendar appointment "All instances" freezes Evolution and corrupts calendar file https://bugs.launchpad.net/bugs/372503 You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is a bug assignee. -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs