Hi Ján, I verified the contacts data in the davical database, and it does not contain invalid XML characters. I even used the more strict 1.0 [\x{0009}\x{000a}\x{000d}\x{0020}-\x{007e}\x{0085}\x{00a0}-\x{d7ff}\x{e000}-\x{fffd}\x{10000}-\x{10ffff}] The debugger shows that CardDAVmate crashes in TypeError: variables.forEach is not a function getContactDataColumn (http://localhost/carddavmate/interface.js:2150:12) AddressbookList.getSortKey (http://localhost/carddavmate/addressbook.js:138:13) I turned out that I had my globalCollectionSort still as [ 'last', 'first', 'middle' ] while the newer functionality requires an array of arrays. However, this change was introduced in 0.13, and I've been running 0.13.1 since september... I cannot explain why it stopped working today... Anyway, I know what to do now. Thanks for the suggestions that helped me out! -- Johan