Index: dav/dav/src/java/org/sakaiproject/dav/DavServlet.java
===================================================================
--- dav/dav/src/java/org/sakaiproject/dav/DavServlet.java	(revision 62747)
+++ dav/dav/src/java/org/sakaiproject/dav/DavServlet.java	(working copy)
@@ -977,7 +977,8 @@
 
 				Authentication a = AuthenticationManager.authenticate(e);
 
-				if (!UsageSessionService.login(a, req, UsageSessionService.EVENT_LOGIN_DAV))
+				if ((UsageSessionService.getSession() == null || UsageSessionService.getSession().isClosed())
+						&& !UsageSessionService.login(a, req, UsageSessionService.EVENT_LOGIN_DAV))
 				{
 					// login failed
 					res.sendError(401);