I am wondering if there is anything special that needs to be changed to get OSX AddressBook desktop client to properly use the CardDAV server. I did have to edit the .plist file on my computer because Addressbook desktop client kept screwing up the path. IPhone with OS 4 (deployed the config through iphone configuration utility) is working perfectly and AddressBook desktop client will sync with the data input by the iphone. Anything added or modified by Addressbook desktop client doesn't post to the server though (i checked in the data folder). Below are two interesting lines that come off the server log when trying to add or modify PUT /addressbooks/__uids__/djackson/addressbook/6AE69D7F-CB3B-414A-9EE7-2AF6B6A69F60-ABSPlugin.vcf HTTP/1.1 2010-08-02 10:49:47-0400 [-] [caldav-0] [-] [twistedcaldav.method.put_addressbook_common#error] u"error: illegal escape sequence: '\\:'" 1) Why is it adding the "ABSPlugin" into the vcf file 2) The illegal escape is only being posted when Addressbook desktop client tries to add or modify. During a sync or startup it doesn't show that error.