Commit #1745(*) to trunk changes the way the server stores ACLs on disk to use a new principal URL form (eg. /principals/__uids__/ FC967643-5B0B-4E22-8657-59832A6AB303). This is not a compatible change with existing data repositories, so if you upgrade your server, any existing data may have trouble with any ACLs that have been written to disk, since the entries won't match the users any more. This was required to fix ticket #159(**) -wsv (*) http://trac.calendarserver.org/projects/calendarserver/changeset/1745 (**) http://trac.calendarserver.org/projects/calendarserver/ticket/159 — Wilfredo Sánchez - wsanchez@apple.com Apple Inc. - Collaboration Services