After changing my WordPress site to a network install all of my OwnCloud client installs failed to check in. The error I saw on the admin page of OwnCloud read “Your web server is not yet properly setup to allow files synchronization because the WebDAV interface seems to be broken.”
The fix for this error is as follows.
Open IIS Manager.
Navigate to your host in the Connections segment of the screen.
Double click Handler Mappings.
Find the PHP module you used right click it and select Edit.
Click Request Restrictions.
Go to the Verbs tab.
Select all verbs.
The sync should start back up on its own. If that doesn’t work there might be another issue.