diff --git a/inc/DAVResource.php b/inc/DAVResource.php
index aa84eb1c..67d786cb 100644
--- a/inc/DAVResource.php
+++ b/inc/DAVResource.php
@@ -1656,6 +1656,7 @@ EOQRY;
 
       case 'DAV::add-member':
         if ( ! $this->_is_collection ) return false;
+        if ( $this->_is_principal ) return false;
         if ( isset($c->post_add_member) && $c->post_add_member === false ) return false;
         $reply->DAVElement( $prop, 'add-member', $reply->href(ConstructURL(DeconstructURL($this->url())).'?add_member') );
         break;
diff --git a/testing/tests/regression-suite/0548-iCal-PROPFIND.result b/testing/tests/regression-suite/0548-iCal-PROPFIND.result
index e8414e50..0a554289 100644
--- a/testing/tests/regression-suite/0548-iCal-PROPFIND.result
+++ b/testing/tests/regression-suite/0548-iCal-PROPFIND.result
@@ -4,8 +4,8 @@ HTTP/1.1 207 Multi-Status
 Date: Dow, 01 Jan 2000 00:00:00 GMT
 DAV: 1, 2, 3, access-control, calendar-access, calendar-schedule
 DAV: extended-mkcol, bind, addressbook, calendar-auto-schedule, calendar-proxy
-ETag: "803271349e94513fdc607adc2fc2df6f"
-Content-Length: 27776
+ETag: "d148cedddc356b211c308738c99d6888"
+Content-Length: 27711
 Content-Type: text/xml; charset="utf-8"
 
 <?xml version="1.0" encoding="utf-8" ?>
@@ -14,9 +14,6 @@ Content-Type: text/xml; charset="utf-8"
   <href>/caldav.php/user1/</href>
   <propstat>
    <prop>
-    <add-member>
-     <href>/caldav.php/user1/?add_member</href>
-    </add-member>
     <current-user-privilege-set>
      <privilege>
       <all/>
@@ -94,6 +91,7 @@ Content-Type: text/xml; charset="utf-8"
   </propstat>
   <propstat>
    <prop>
+    <add-member/>
     <C:allowed-sharing-modes/>
     <M:bulk-requests/>
     <A:calendar-color/>