IIS7 error when enabling Wordpress Permalinks URL Rewriting

I wanted to turn on Permalinks in Wordpress to use the following custom structure.

/%year%/%postname%/


I added the following section to my web.config file.

<rewrite>
    <rules>
 <rule name="wordpress" patternSyntax="Wildcard">
     <match url="*" />
     <conditions>
  <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
  <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
     </conditions>
     <action type="Rewrite" url="index.php" />
 </rule>
    </rules>
</rewrite>

After updating the web.config and browsing to one of my posts, I encounter the following IIS7 error:
Cannot add duplicate collection entry of type 'rule' with unique key attribute 'name' set to 'wordpress'


When I’ve encountered this error in the past, it hasn’t been a direct problem with my web.config, but has been a problem with inherited sections or values from a parent website config or one of the default environment configurations. With that in mind, I added the following line to remove any existing rules with the name “wordpress” before trying to add my own.

<remove name="wordpress"/>
The complete web.config section looked like this and cleared up the error.

<rewrite>
    <rules>
 <remove name="wordpress"/>
 <rule name="wordpress" patternSyntax="Wildcard">
     <match url="*" />
     <conditions>
  <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
  <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
     </conditions>
     <action type="Rewrite" url="index.php" />
 </rule>
    </rules>
</rewrite>

Hope this helps someone!