Today one of my colleague came across a WebDAV issue where a customer was getting the error “Error: Cannot add duplicate collection entry of type 'add' with combined key attributes 'users, roles, path' respectively set to '*, , *'” when he would try to open WebDAV Authoring Rules feature in IIS 7.

The error message clearly states that we have duplicate entry in the applicationHost.config file.

<webdav>
    <authoringRules>
        <add users="*" path="*" access="Read" /> -----------> Line 965
    </authoringRules>
</webdav>

Searched for the same text and found it at system.webServer\webdav\authoringRules.

Solution here is, the issue happens because we are missing the <clear /> at the top under authoringRules section. Added the same and now we are able to access Authoring Rules fine in WebDAV.

applicationHost.config looks like this:

        <system.webServer>
            <webdav>
                <authoringRules>
                    <clear />  -----------> missing this
                    <add users="Administrator" roles="" path="*" access="Read, Write, Source" />
                    <add users="*" roles="" path="*" access="Read" />
                </authoringRules>
            </webdav>
        </system.webServer>

The keyword <clear /> is used to ignore the global setting and use the ones we configure at the site level.

Hope this helps,
Vivek Kumbhar

Quote of the day:
This country has come to feel the same when Congress is in session as when the baby gets hold of a hammer. - Will Rogers