Hello, i already wrote those suggestions on the mailing list, but i thought to put them here in a clearer (and more visible) manner. Here it is: I had troubles making CalDAV/CardDAV functionality of ownCloud work under Windows 7 + IIS, and i solved applying those two corrections to my environment. 1) Make sure the PHP handler get ALL the http verbs: a) On IIS Manager, select the web server/folder where ownCloud is installed. b) Open 'Handler Mapping' c) In the 'Path' column, look for the '*.php' entry (normally it's 'PHP53_via_FastCGI') and double click it. d) Click 'Request Restrictions...' button e) On 'Verbs' tab, make sure 'All verbs' is selected 2) Completely remove WebDAV feature of IIS a) Open Control Panel b) Under Programs/Program and Features, chose 'Turn Windows Features on or off' c) Select Internet Information Services, World Wide Web Service, Common HTTP Features d) Make sure 'WebDAV publishing' is unchecked Take a look at this post for more information: http://groups.google.com/group/sabredav-discuss/msg/375d53a474899d44 Of course, this is a problem for those that need IIS WebDAV feature for other sites hosted on the same server. I don't know if there is a workaround. I think it would be nice to publish those suggestions on the installation guidelines on ownCloud site (http://owncloud.org/install/advanced/), or wherever you think appropriate. Thank you, and keep up the good work.